Prime Minister John Key is continuing to support ACT Party leader John Banks who remains embroiled in a local body election donations scandal.
The opposition Labour Party piled on the pressure this week after the police released their file on donations given to the ACT leader for his 2010 Auckland mayoral campaign.
The file includes evidence from internet piracy accused Kim Dotcom that at a meeting in June 2010 Mr Banks asked for a $50,000 donation to be split into $25,000 cheques so he wouldn't have to declare where they came from.
Mr Banks declared the donations as anonymous and has said publicly he did not know that Dotcom made a donation to his campaign.
The MP holds ministerial portfolios under a support agreement with National.
Mr Key told TVNZ's Q+A programme on Sunday that he had not read the police report "and I'm not going to".
"The test for whether someone can be a minister is whether they enjoy my confidence. If a minister tells me this is my position and this is what I've done, I accept their word in good faith unless it's proven otherwise," Mr Key said.
He said the issue was a politically motivated attack by Labour.
"We've been given assurances and I accept the minister at his word," Mr Key said.
He said the law on political donations was badly drafted and it was being fixed.
"The fact that someone tells you they may make you a donation doesn't mean under the old electoral law that you know that they have," Mr Key said.