"It would change dramatically the way I conduct my business and the way I do things because I would have to be on the lookout for [covert recording] every second. It's all very well starting with me, but it would move to a lot of other New Zealanders.
Key said that one of the good things about being the Prime Minster of New Zealand was being able to "get out there and meet people all of the time."
Mr Key then jumped into his ground limo, ignoring further questions from the media.
Walkout
Mr Key walked out of a media stand-up earlier today after continued questioning about the incident.
He had been meeting media after a speech at the Federated Farmers national conference at Westpac Stadium in Wellington.
He repeatedly said, in response to questions around the tape, that he and New Zealanders were interested in issues such as the economy (not the tape).
In an extraordinary response, when journalists continued to ask him about the tape, he then stormed off.
At a photo-shoot in the Prime Minister's office at 12.30pm, Mr Key reportedly said the teacup tape was a matter for police and was not important to New Zealanders.
"I'm not in the slightest upset. But I'm interested in talking about the issues that matter," he told Newstalk ZB.
Asked if the teacup tape was an issue that mattered, he said: "Not in the slightest. That's a matter for the police."
Goff launches stinging attack
Key's walk-out followed a stinging attack from Labour leader Phil Goff, who called the tape "a political embarrassment".
Mr Key now had a credibility issue on his hands, Mr Goff said, and if hints about what was said in that conversation about Act's future leadership were correct, he should come clean.
"If some of the reports are correct about axing Dr Brash, be honest with the electorate beforehand what they're trying to do, not afterwards."
He said if Mr Key had made disparaging comments about elderly NZ First voters, it was disgusting.
"That generation helped build New Zealand. They might not share John Key's views or my views, but you shouldn't ever be disparaging."
Peters: 'Tea tape' not 'bland'
Meanwhile, Winston Peters is confident the 'tea tape' will be released, unveiling derogatory comments made by Mr Key.
Mr Peters told Radio New Zealand this morning he was privy to the conversation recorded by freelance cameraman Bradley Ambrose between Mr Key and Act candidate John Banks during a symbolic cup of tea in a cafe last week.
The recording was given to the Herald on Sunday, who were refused permission by the National Party to print a transcript of the recording.
Mr Key has since called the contents of the tape "bland'' and has refused to release the tapes on principle, citing the covert recording as `News of the World tactics'.
Mr Peters said while he knew what was said between the pair, he refused to detail the comments made - but said the contents of the tape would leave many people reeling.
He said the tapes recorded Mr Key making derogatory remarks about a handful of groups and people, including the leader of the Act Party Don Brash.
"The elderly people of this country will be pretty brassed off. But the real issue is that he'd dumped on Mr Brash in a big way, he's dumped on the deal,'' he told Radio New Zealand.
Mr Peters said the tapes should and would be released to New Zealanders.
"There's no way the matter will be closed down now ... Why not just let it go in the public interest?''
"There's a public interest test, and I think it passes that test as capable of being published so I do not think it's illegal.''
Labour party leader Phil Goff has called the incident a 'farce' and a media stunt where photographers and journalists had their faces pressed up against the glass.
Mr Goff said he hadn't heard the tape, and didn't know what was on it.
He said this was not the major issue facing New Zealand at the moment, and the public needed to shift their focus to issues such as the sale of public assets.