A National MP says he was concerned by an "aggressive" Kim Dotcom at a function, threatening to bring down Act Party MP John Banks and the National Government.

The encounter last year between Mr Dotcom and National MP for the Rodney electorate, Mark Mitchell, was relayed to the High Court at Auckland today, where Banks is on trial for filing a false electoral return over his failed 2010 Auckland mayoralty tilt.

Mr Mitchell said he was approached by Mr Dotcom at a BBQ last year.

"Towards me he was quite aggressive. It didn't offend me so much but it certainly had an impact on my wife, and he stated to me comments like, 'I've got the information, I'm going to destroy [Prime Minister] John Key. I'm going to take down John Banks and I'm going to take down this National Government. I can and I will destroy them'."


Crown prosecutor Paul Dacre, QC, accused Mr Mitchell of adding to his evidence as he went along, but Mr Mitchell denied this.

Meanwhile, two sharply contrasting versions have emerged about what happened when Banks and his wife had lunch at the internet entrepreneur's mansion in June 2010.

The court has heard from Crown witnesses saying Mr Dotcom offered to give Banks a $50,000 donation.

Mr Dotcom and his estranged wife Mona Dotcom said Banks asked for the money to be split in two, so it could be kept anonymous.

But the defence says the Dotcoms' evidence and that of other former Dotcom employees is an "absolute litany of untruths".

Banks' wife Amanda Banks was the first defence witness called, and she said today the only discussion she heard about the mayoralty campaign was to do with emailing potential voters.

Neither she nor Mrs Dotcom were present when donations were discussed, Mrs Banks said, which contrasted with Mrs Dotcom's evidence last week that she heard Banks ask for the donation to be split.

Mrs Banks' memories of the lunch also differed from Mr and Mrs Dotcom and other Dotcom workers over who was present.


Driving back to Auckland, Mrs Banks and her husband "came to the conclusion that there probably wouldn't be support for the campaign" from the Dotcoms.

"A lot of people have the look of opulence but don't necessarily have a lot of cash," she said.

Before Justice Edwin Wylie and no jury, Banks is defending a charge of filing a false electoral return where he allegedly knowingly received political donations from Mr Dotcom and SkyCity that were recorded as anonymous.

The allegations against Banks relate to two $25,000 donations from Megastuff Ltd on Mr Dotcom's behalf in June 2010 and $15,000 from SkyCity in May that year.

"The essence of the defence case is quite simple. Mr Banks did not do anything wrong. He did not know of any falsity in any return. He relied on his trusted campaign treasurer [Lance] Hutchison, a man himself of immense integrity," Banks' lawyer David Jones, QC, said in opening the defence case.

"Before [Banks signed the return] he asked Mr Hutchison 'Can I sign this in good faith? Is it accurate? Is it true?' He gets the affirmative and he signs."

The final prosecution witness, SkyCity chief executive Nigel Morrison, said he had a short meeting with Banks in early May 2010 to give him a $15,000 donation, which was in an envelope.

SkyCity had decided to donate money to the campaigns of both Banks and his main rival for the mayoralty, Len Brown, after Mr Brown approached the company for a donation.

"We had no desire for it to be anonymous," Mr Morrison said of the payments.

Last week Banks' campaign treasurer Mr Hutchison said after receiving the cheque from SkyCity, he phoned somebody there and was asked if the donation could stay anonymous.

Tomorrow the court is expected to hear from Banks' campaign worker Scott Campbell and character witnesses.