Lawyers for the New Zealand First leader, Winston Peters, are due to meet an investigator from the Serious Fraud Office on Saturday.
Mr Peters last night stepped aside as Foreign Affairs Minister on Friday evening, while a SFO investigation is held into donations to his party.
Prime Minister Helen Clark has taken over his ministerial portfolios and says Mr Peters is keen to defend his reputation.
But National Party leader John Key says that reputation is now in tatters.
The Green Party says Mr Peters could not have represented New Zealand overseas while the investigation was ongoing.
ACT leader Rodney Hide says Miss Clark should have gone further and sacked him.
Miss Clark says Mr Peters will be reinstated as Foreign Affairs Minister if the Serious Fraud Office clears him.
Mr Peters' lawyer, Peter Williams QC, says he has seen a statement from the Spencer Trust, which received the donations, which shows the money was used as intended.
He says the documentation will be shown to a senior SFO executive.
Mr Williams says it should have been examined before his client was subjected to the accusations.
The Serious Fraud Office announced on Thursday it will look into allegations that donations to New Zealand First from Sir Robert Jones and the Vela family did not reach their intended destination.
The Privileges Committee has invited Mr Peters, his lawyer Brian Henry and expatriate businessman Owen Glenn to give evidence next week.
The committee is considering whether Mr Peters should have declared a $100,000 donation from Mr Glenn towards legal bills in 2005.
The committee is expected to hold a closed three-hour session on Thursday morning.
Miss Clark said on Thursday that Mr Glenn told her in February that the New Zealand First leader had approached him for money.