Winston Peters wants Parliament's privileges committee to hold an open meeting tomorrow and he intends making another personal appearance if it does.
The New Zealand First leader is understood to be upset because he believes the Serious Fraud Office has submitted written evidence to the committee, which is investigating a $100,000 donation from billionaire Owen Glenn.
The SFO is holding its own inquiry into two other donations, and has not so far had any role in the committee's investigation.
Mr Peters has written to the committee, which has a closed meeting scheduled to start at 1.30 tomorrow afternoon, saying it should be thrown open because he and the public have a right to know what is going on.
Committee chairman Simon Power would not comment tonight.
"What is going to occur tomorrow is a matter for the committee," he told NZPA.
As the latest odd twist to the story developed, Prime Minister Helen Clark said she was going to wait for the outcome of both inquiries before deciding whether to sack Mr Peters.
That means he could hold his ministerial warrant through to the election.
Mr Peters has stood down from his portfolios while the SFO carries out its investigation.
The privileges committee is expected to report on September 23 but there is no deadline for the SFO.
"I'm waiting to hear from the privileges committee, I'm also waiting to hear from the Serious Fraud Office," Miss Clark told reporters.
"There are a number of processes going on and they are far from being exhausted."
The police are also investigating an undeclared donation to NZ First.
The National Party has said it will not have anything to do with Mr Peters or his party after the election and has been calling on Miss Clark to sack him.
She said earlier this week there would need to be "devastating" evidence laid against him before she removed his warrant, and today she said that had not happened.
The committee yesterday heard evidence from Mr Peters' lawyer, Brian Henry, about the $100,000 donation from billionaire Owen Glenn.
It was paid to Mr Henry in December 2005 to cover fees for legal work he had done for Mr Peters.
Mr Glenn has told the committee Mr Peters asked for it, but Mr Peters denies that and says he did not know anything about it until July this year.
Miss Clark does not sit on the committee but her deputy Michael Cullen does, as well as senior cabinet minister Lianne Dalziel.
Miss Clark said she consulted them after yesterday's hearing.
"Their strong advice was to let the process continue," she said.
"They say the conflict of evidence is there, as it has been all the way through."
The committee does not intend calling any more witnesses.