SkyCity publicly donated money to both mayoral candidates although it was listed as an "anonymous" donation by Mr Banks. Questions about the donation came after Mr Banks emerged as the Government's one-vote majority on gambling concessions sought by SkyCity.
Dotcom then stepped forward to say he had also donated money to Mr Banks, who had asked it be paid in two lots of $25,000 so it could be claimed as an "anonymous" donation.
Mr Banks, who has denied the claim, filed accounts showing five donations at the $25,000 level.
The Herald has obtained paperwork showing the development of the campaign to get Mr Banks elected. The "mentor group" had four people placed in charge of fundraising including Mr Simpson and fellow former National Party board member Michelle Boag. The other two were real estate agent Graham Wall and Auckland councillor Cameron Brewer.
Mr Simpson said he had only "minor involvement" in the campaign. He said the "fundraising" reference was "to make it look like I was doing something".
He said the "mentor group" rarely canvassed donations and only ever spoke of it in general terms. "I've never met Kim Dotcom or spoken to him."
He said he had not been asked about the campaign by Prime Minister John Key. Mr Key had also not spoken to Mr Banks about the issue.
Ms Boag, who has said she knew nothing of the donation, said it was not appropriate to make any comment because of the police investigation.
Mr Brewer said he had little to do with the campaign after deciding to stand for council himself.
Mr Wall said he was a "good friend" of Mr Banks and had little to say. "He's a patriot who has given 40 years of service to his country."
Meanwhile, Mr Banks yesterday confirmed he got a discounted deal at Kim Dotcom's favourite Hong Kong hotel during his stay there last year after denying it the night before.
But he says he negotiated the discount himself.
"I negotiated the price for the hotel room and I paid for everything in Hong Kong," he said.
"I always negotiate prices down, I don't believe in paying the rack rate in a hotel.
"The hotel room was so expensive I even paid for it with my wife's credit card."
Mr Banks said his association with Dotcom was not the reason he was able to negotiate a lower charge for the room.
Opposition MPs have called for Prime Minister John Key to stand down Mr Banks as a minister while police investigate complaints over donations to Mr Banks.
PHONE RECORDS WITHHELD
Phone records covering the month in which Act leader John Banks visited internet tycoon Kim Dotcom are being withheld for police inspection.
The records, held by the Auckland Council, would be a key factor in the investigation into questions over donations made to Mr Banks' campaign to be mayor in 2010.
Police are investigating complaints that Mr Banks knew details of three anonymous donations made to his campaign.
A donation of $15,000 by SkyCity was listed as anonymous, as were two of $25,000 made by Dotcom.
Dotcom said he was asked to make the donations in two separate amounts in June 2010. He also claimed Banks rang him later.
The Herald asked the council for the date, time and number of calls made to Dotcom's Hong Kong mobile during June 2010.
The council refused to release the bills because it could interfere in a police investigation.
A spokesman for the council said police had not yet asked for the phone bill.
