In a statement read out to the High Court in London, he said: "An allegation of match-fixing, is in my view, the most damaging comment that can ever be made.
"To state that a professional cricketer is a cheat ... it goes to the core of a player's integrity."
Cairns was Tuffey's captain in the Chandigarh Lions in the now-defunct private Indian Cricket League (ICL).
Cairns is now suing the former chairman of the professional Indian Premier League (IPL), Lalit Modi, for claiming on Twitter that Cairns was involved in match-fixing in the last two of his three editions of the Twenty20 league in 2008.
The July 2010 tweet was picked up by the ESPN-owned website Cricinfo, which later withdrew the report, issued an apology and paid damages. But Modi has refused to apologise as he maintains the comments are true.
Cairns' ICL career ended when he was axed after three games in the third edition for not declaring an ankle injury, exacerbated by a 1000km charity walk he did in memory of his late sister. He'd signed the three-year contract in 2007.
But Modi's defence alleges his injury was a "cover-up" to mask a match-fixing allegation.
He is backed by the ICL's anti-corruption officer at the time, a former Australian policeman who said Cairns was compared to former South African cricketer Hansie Cronje, who was banned from the sport in 2000 for fixing matches.
Modi claims Cairns conspired with Dinesh Mongia, a former Indian international, to "put pressure on younger players to underperform" and statements from players said they did so because they wanted to go on the pitch.
Cairns has been questioned about his involvement with diamond-trading company Vijay Dimon in Dubai, and the large sums of money he received from them prior to the third edition of the IPL.
He lived in the United Arab Emirates while playing for the team with his Australian wife Melanie, nee Croser, who was his girlfriend at the time.
He is asking the court for substantial damages and an injunction preventing a repeat of the allegations.
Cairns and his wife have flown over from their home in Canberra where they live with their 11-month-old daughter Isabel.
The case, which is expected to finish next week, started this week inside the 130-year-old Royal Courts of Justice building, which houses the country's High Court and the Court of Appeal on The Strand in the political district of Westminster.
The public gallery has been packed each day - mainly with law students from the nearby City University intrigued by the landmark case.
One says it will "open the floodgates" for others to sue over comments made on the social networking site.
Cairns sits in the front of the court, at the end of the first row next to his his wife and one of his three lawyers.
He looks restless but listens intently, screwing up his face and rolling his eyes when he hears something he doesn't like, and furiously scribbling notes as witnesses speak before showing one of his legal team his musings.
His wife, professional basketballer-turned-sports marketing manager Mel Cairns, concentrates on a computer screen in front of her which shows a transcript of everything said in the court presided over by Justice David Bean.
Modi sits in the public gallery, with about half a dozen colleagues and family members who have also come over from India, studying a large stack of papers.
Cairns gave very animated evidence during the first two days of the trial, at times slamming his glass of water on the bench in front of him while answering questions from the defence.
He said the allegations were "wholly untrue" and left him angry and saddened.
"The defendant's allegations have also had a profound effect on my personal and private life. It put a strain on my marriage.
"It hurts that my wife may think that I am not the man she thought I was.
"It hurts me too that friends, many of whom are former cricketing foes, will question my integrity as a man and a sportsman and that all I achieved in the great game of cricket is dust."
Counsel for Modi, Ronald Thwaites, QC, questioned why Cairns had walked away with so little fuss from a contract that still owed him more than two seasons and $750,000.
The lawyer told him: "You left with your tail between your legs in the hope the match fixing wouldn't leak out."
But Cairns claimed he did not complain because he wanted to work his way back into the league.
The court heard that Rajesh Sharma, a bowler with Chandigarh, said he had raised concerns about match-fixing during the second edition of the ICL but was told by Cairns and Mongia to keep quiet or he would be removed from the team.
Cairns denied the conversation took place but said he had spoken to Sharma and two other players about their levels of performance.
Another player, Gaurav Gupta, alleged that he had been told by Mongia that Cairns would give him money for fixing matches.
He said in one match he had been told to score five runs or less and that it was understood a player could earn $20,000 if they agreed to engage in fixing.
In a statement read by Thwaites, Gupta said: "Chris Cairns would give me some matches and all I would have to do is listen to him for instructions.
"All I wanted at this stage was confirmation of some certainty that I would be able to play.
"[He] made it clear that if I wanted to play matches this is what I had to do.
"He made it clear that loads of people were doing the same thing."
Cairns denied the allegation, saying: "Players only stayed in my team based on performance."
Another player, Amit Uniyal said he was told to "bowl loose balls" in order to keep his place in the side, while Love Ablish was allegedly instructed to bowl a no-ball.
The players are expected to give evidence by video link from India next week and former South African all-rounder Andrew Hall will also to be called as a witness for Modi.
Bank statements submitted to the court show Cairns received two separate payments from Vijay Dimon, totalling AED 600,000 ($160,000), into an account in Dubai.
Made in August and September of 2008, Cairns said the payments were for relocation costs and appearances at dinners and events.
A third payment, bringing the total to AED 900,000 ($250,000), was made to his account in 2009, after which his association with Vijay Dimon continued only on an "occasional basis".
There was no formal contract signed with the company and Thwaites said: "You have drawn suspicion upon yourself. You must be aware that to take large payments immediately before a tournament in a country where match-fixing is rife invites suspicion?"
Cairns' counsel, Andrew Caldecott QC, said that on October 26, 2008, while his team were staying at the Shangri La hotel in New Delhi, Cairns was called to an ICL directors' meeting in one of the rooms where his denial of rumours of his alleged involvement in match-fixing appeared to be accepted.
He was subsequently suspended over his injury.
"No specific charges of match-fixing were ever put to Mr Cairns. No names of any accusers were mentioned.
"He was never informed after his departure that statements had been taken - mainly later - from Indian players alleging corrupt activity by various players including him."
The court heard that Cairns called his legal adviser and friend Andrew Fitch-Holland in Britain telling him rumours had started appearing on Indian gossip websites about him being axed for match-fixing.
He asked whether he should "shut it down".
But Fitch-Holland told the court: "Some spotty teenager in Punjab said it ... It's pub talk, it's complete bullshit, it's garbage. If Cricinfo said it or a reputable newspaper covered it, we would deal with it. I do not think it's time to start pulling out the big guns ...
"If it's tomorrow's fish and chip paper, it's not worth it.
"It would have been a disproportionate reaction to what I believe is low-level tittle tattle."
He also spoke about his friend's mindset that year after splitting from his second wife Carin, who subsequently moved with their children to South Africa.
"All the holidays in the world don't make up for being able to cohabitate with your children. The pressure of a failing marriage, being apart from his children, having to live a life of an international cricketer and to focus on having to develop a new relationship is upsetting.
"Chris was supposed to go to Dubai with Carin, subsequently he went with Mel.
"Dubai was the ideal location. He could fly to India, he could fly to South Africa to see his kids and he could be at home and paying a low tax rate. Everyone wins."
Mel Cairns gave evidence on Wednesday, her voice quavering after being asked if she questioned her husband over the allegations.
"There was a time when I did ask him and it was the most horrible question I have ever had to ask. I'm completely ashamed and embarrassed that I had to ask him that, but I did ask him."
He told her "no, absolutely not", she said, adding: "When you see the world media, over and over accusing the man you love of something ... of course I want to believe him and I do believe him."
Thwaites asked her, with her background in public relations, why she didn't suggest her husband get a letter of termination setting out the reasons why he was axed.
She said: "Why would I? I don't have anything to do with Chris' cricketing negotiations. I was his girlfriend at the time."
Cairns said she knew about the allegations on Indian gossip sites because she had a Google alert on her husband, admitting: "There were a lot of articles on the internet about Chris and me, about Chris' split [with Carin]. So I would often check anything about Chris and myself."
Former anti-corruption officer Howard Beer, a former detective senior constable in Australia, said on Thursday he had "no doubts" Cairns was involved in match-fixing, based on the evidence he gathered.
He recalled telling Cairns' New Zealand teammate Hamish Marshall, who also played in the ICL, it was "no secret Cairns had been sent home for match-fixing".
He said the October meeting involved a conversation between Cairns and then ICL executive director, former England captain Tony Greig, about corruption allegations.
In the meeting, Greig allegedly compared Cairns to disgraced former South African Hansie Cronje, who was banned from the sport in 2000.
"Don't take this the wrong way, Cairnsy, but nobody would have thought that Hansie Cronje was involved in match-fixing," Greig allegedly said to Cairns, Beer told the court.
Beer said he did not stay in the meeting until the end and the next day learned Cairns had been dismissed.
He said he was told by Greig the league would announce that Cairns failed to declare an injury as the reason for his suspension.
Beer said the ICL then put his corruption inquiry on hold.
"I had concerns that the way the procedure was at that time, there was insufficient evidence to substantiate allegations of match fixing against Mr Cairns," he said.
The case is expected to last 10 days, finishing next week.
KEY PLAYERS
Lalit Modi: Accused Chris Cairns of match-fixing via social media site Twitter in January 2010. Now sued by Cairns who alleges Modi's claims are false. Modi was suspended as commissioner of the Indian Premier League in April 2010 over separate allegations of match-fixing.
Chris Cairns: Former New Zealand cricketer, who was regarded in his prime as one of the world's best all-rounders. Accused of receiving two instalments of $100,000 for match-fixing while captain of Indian Cricket League team Chandigarh Lions between 2007 and 2008.
Howard Beer: Former Indian Cricket League anti-corruption officer. Told the High Court in London that he believed Cairns had been involved in match-fixing. Andrew Hall:Former South African all-rounder is due to be called as a witness for Modi next week.
Mel Cairns (nee Croser): Wife of Chris Cairns. Gave evidence on third day of the trial in support of her husband. Believes allegations are false.
