The Opposition claims the dinner was about Ms Collins going to bat for the company that employs her husband, after it had asked for ministerial assistance to overcome obstacles to its milk exports to China following the Fonterra botulism scare.
Peters' latest claims
Last night, Mr Peters released what he said was "an important Chinese import clearance document" from AQSIQ for Oravida's milk posted on the internet by the company about eight weeks after Ms Collins' Beijing dinner and just a few days before the company donated $30,000 to National on December 23.
"This suggests Oravida is boasting about having received clearance to export again from China's General Administration of Quality Supervision, Inspection and Quarantine [AQSIQ]," Mr Peters said.
"This is serious evidence that Oravida did benefit from Minister Collins' visit ... Their gratitude was shown three days later when the National Party received a $30,000 donation from them."
Mr Peters claimed to have further evidence that would implicate Ms Collins.
Prime Minister John Key told TV's Firstline that the clearance document released by Mr Peters was a "stock standard thing'' which was issued all the time.
"So they put it up on the website, lots of people do, it's issued by the Chinese government, it's got nothing to do with the New Zealand Government.
"Yes, we accept and Judith accepts the advice of the Cabinet office - which is the combination of events could lead to the perception of a conflict of interest - but outside of that, actually nothing has changed and nothing is inconsistent.''
Mr Key said the issue highlighted the dangers of Twitter, and Ms Collins' break from Parliament would present a good opportunity for her to take a break from that too.
"I think it's sensible for her not to be engaging in Twitter and reading some of the trolls and people that are on that stuff.
"I don't engage in that. I put tweets out from time-to-time, or my office does, that are used as a sort of broadcast mechanism for understanding what I've done or a particular thing that's happened or something that's a little bit quirky or interesting.
"But I think there's a real danger in politicians engaging in this stuff," he told Firstline.
"There are frankly, people who get on there - they're nasty and they've got a particular agenda - and I think Judith's let a few of those people get under her skin.
"She's a good minister. She knows what she's doing. She should take a couple of days of rest and relaxation, come back and be the strong minister that we know she is."
At National's northern regional conference over the weekend, Ms Collins lashed out at TVNZ parliamentary reporter Katie Bradford, for which she has now apologised.
Yesterday, Mr Key said he had discussed those "inappropriate" comments with Ms Collins on Sunday.
They were "a reflection of the fact she was letting things get under her skin and I think she would regret that," he said.
"We'll be encouraging her ... just to take a few days off."
But Ms Collins must front up in Parliament today and tomorrow, when the Opposition will grill her on Mr Peters' claims and a fresh Labour attack based on an Mfat document showing her visit to Oravida's Shanghai offices days after her Beijing dinner was officially described as being "to increase the profile of a successful importer and distributor of New Zealand products into China".
Mr Key said he had had a "cursory look" through the documents referred to by Labour, and "there will be the normal political questions that will get asked and people will be able to work out why the Opposition asks those".
Cunliffe: 'She should be gone'
Labour Party leader David Cunliffe told TVNZ's Breakfast programme this morning he would have sacked Ms Collins if she was a minister under his government.
"She's been found clearly guilty of a very serious set of conflicts of interest around the company on which her husband is a board member, which is a donor to the National Party.
"It's a serious situation. She should have been sacked before now.''
The MFAT documents showed new information around the Oravida dinner, which should force Ms Collins' ministerial resignation, Mr Cunliffe said.
"What these papers make clear is that it was no chance meeting between a senior Chinese official and the chairman of Oravida and (Ms Collins).
"They sought the meeting weeks before, MFAT was involved in setting it up, MFAT was initially involved in providing an official briefing, and none of that is just another private dinner.''
Ms Collins had "clearly told an untruth to the Prime Minister and to the public'', Mr Cunliffe said.
"She should be gone.''
The situation left Mr Key in a "bizarre situation'' with Ms Collins taking time off at the end of the week, he said.
"If any other worker is guilty of lying to the boss, is guilty of lying to the public, they don't get a $5000 paid holiday for their trouble.''
He said Ms Collins was the Minister of Justice and a trained lawyer, and she should know when there was a conflict of interest.
The Oravida saga
• August 2013: Oravida's managing director Julia Xu asks Trade Minister Tim Groser and Primary Industries Minister Nathan Guy for help to tackle a new testing regime which was blocking its milk imports to China.
• Early October: Oravida invites Justice Minister Judith Collins to visit its Shanghai offices and to also go to dinner in Beijing.
• October 20: Ms Collins arrives in Beijing where she attends lunch and the dinner with Oravida's Stone Shi and a senior Chinese border control official.
• October 23: Ms Collins visits Oravida's Shanghai offices.
• December 20: On its website Oravida posts an import certificate from Chinese authorities approving its milk imports.
• December 23: Oravida donates $30,000 to the National Party.
• March 12: Ms Collins put on notice by Mr Key after admitting she met Mr Shi on two further occasions than she had previously said.
• April 17: Ms Collins admits she briefed the NZ ambassador to Beijing on the Beijing dinner.
• May 2: Foreign Affairs documents reveal Ms Collins' office also asked for an official briefing.
- additional reporting APNZ