The Prime Minister is adamant John Banks will remain in Cabinet despite new police evidence revealing he knew the source of so-called anonymous donations.
Documents released by the Labour Party reveal that 10 wealthy donors, including internet tycoon Dotcom, were targeted by Banks' campaign team for $25,000 each.
But John Key said he would not fire Banks in the wake of the new information.
"Nothing's changed when it comes to that position," the PM said.
"I haven't read the full report but what I've seen in terms of the media&this is a politically motivated attack."
The documents stem from a police inquiry this year over anonymous donations to Banks' unsuccessful Auckland mayoral campaign in 2010.
In a sworn statement, Kim Dotcom said he offered Banks $50,000 for his mayoral campaign during a June 2010 meeting at his Coastsville mansion. Banks then requested the donation be split in two so he "would not have to declare where it came from".
Dotcom says Banks then said: "I want to help you Kim and I can help you more effectively if no one knows about this donation."
Labour's deputy leader Grant Robertson told TV ONE's Breakfast today that if police cannot charge Banks over the donations, Key must get rid of him.
"Everything in this document points to the fact that John Banks absolutely knew what was going on with the donations. He knew they weren't anonymous donations," Robertson said.
"And I think John Key is the person now who has to apply the test. Maybe the police say they can't prosecute, but John Key's got this man in his Cabinet right now."
The police evidence also reveals Dotcom's lawyer asked the Epsom MP to see if he could get Dotcom an extra mattress for his Mount Eden Prison cell.
In his statement, lawyer Greg Towers says Banks told him: "As much as he wished to publicly support Kim, that may backfire on Kim if it became known about the election support."
Detectives earlier found Banks solicited money for the campaign from Dotcom, but were unable to establish whether he knew two gifts of $25,000 came from the German millionaire. The return was completed by campaign volunteers.
Banks 'never wanted to see bank statements'
The police documents show that Banks' campaign treasurer said in an interview: "We initially drew up people to approach for donations; these included people of the NBR Rich List.
"Our donation target was 10 donations of $25,000. We knew we would need to raise in the vicinity of a million dollars, which we considered ridiculous that candidates for a local body election should need to do this."
The treasurer said all anonymous donations were notated on a bank statement.
"He (Banks) never wanted to see the bank statements and he did not want to know where the money came from."
The treasurer said a legal firm advised the campaign team on the legislation behind donations and the briefing made them believe "anonymous" included someone who asked not to be identified as a donor.
"We never told Banks where the money came from as he simply wasn't interested," the treasurer told police.
The treasurer said Banks was the largest donor to the campaign, donating $80,000-$90,000 of his own money.
The decision to list a $15,000 SkyCity donation as "anonymous" is what led to the police inquiry, the documents show.
The treasurer said the campaign received a cheque from SkyCity in the post. The treasurer said they called "this person who I know" in the SkyCity legal department to ask whether it was an anonymous donation.
"The advice I was given from them was that they wanted to remain anonymous."
This led to questions when a donation to Mayor Len Brown during his campaign was later revealed.
The Labour Party filed a complaint with police after it was exposed that SkyCity had also made a donation to Banks' campaign.