Businessman Owen Glenn has sent a second letter to Parliament's privileges committee reiterating that New Zealand First leader Winston Peters sought a donation from him.
Mr Peters was appearing before the committee for a second time on Thursday morning.
Mr Glenn, who is based in Monaco, will appear in person to answer questions on Tuesday.
The privileges committee is considering whether Mr Peters should have declared the $100,000 donation from Mr Glenn towards the cost of an electoral petition in Tauranga after the 2005 election. Mr Peters claimed that National Party MP Bob Clarkson had overspent on his successful campaign.
Mr Peters gave no evidence to the committee on Thursday, and instead his lawyer Peter Williams, QC, attempted to give an address on the history of the case.
This was cut short as the committee chair, National's Simon Power, ruled that he could only address procedural matters, however, Mr Williams persisted.
"If you are going to suffocate me, then this will be a sad day for democracy in this country," he said.
"I will refer to the matters of procedure but it is necessary for me to develop my argument. I cannot be stopped - these matters are not controversial, even."
Mr Power replied that the matters were well known to the committee and are part of the substantive matter before the committee.
As the hearing became more heated, and several members raised points of order, Mr Power gave Mr Williams a final warning, and his statement was tabled.
Mr Peters has previously argued he only found out about the donation through his lawyer in July, and that he had never approached Mr Glenn for the money.
In a letter released last week, Mr Glenn said not only had Mr Peters sought the donation, he later thanked Mr Glenn for it.
The committee on Thursday released a second letter from Mr Glenn, which reiterates that Mr Peters solicited the donation from him.
Prime Minister Helen Clark revealed last Thursday that Mr Glenn told her in February Mr Peters had approached him for money.
She says Mr Glenn told her about the payment when the two met at the opening of Auckland University's business school.
The committee may discuss whether to call her to give evidence at a later date.
Mr Peters has been stood down from his ministerial portfolios, including that of Foreign Affairs Minister, while the Serious Fraud Office investigates other donations to his party.
The Serious Fraud Office announced last Thursday it was investigating donations to New Zealand First by businessman Sir Robert Jones and the racing industry's Vela family.