Kim Dotcom claims he has proof that Prime Minister John Key lied about not knowing who the Megaupload millionaire was until just before the raid on his Coatesville mansion.

But Dotcom says he will not reveal his evidence until he is in court.

Dotcom told TVNZ's Q+A programme this morning that Mr Key knew about the German-born millionaire living in New Zealand before the Prime Minister was briefed on January 19 about the next day's planned police raid on his mansion.

Mr Key today denied the allegation by Dotcom.


A spokesman for the Prime Minister said he "stands by his earlier statements" about when he first knew about the internet entrepreneur.

"He is running around naked and telling everybody he has clothes on," Dotcom told Q+A.

"Everyone can see he's naked. It doesn't make any sense.

"I know for a fact that John Key knew before January 19.

"It's going to be a topic in our court hearing so I don't want to reveal too much."

Dotcom is fighting extradition to the US where authorities allege copyright, money laundering and fraud charges in relation to his Megaupload file-sharing website.

He said aid there was "only one reason" why Mr Key would "not be upfront and honest".

Dotcom claimed it showed there was political interference in the investigation and proving that could "stop the whole extradition procedure".

"If we can show that the Government here has had an active role in the magnitude of this whole case and had a proactive role - rather than a reactive role - to impress the United States government ... it's a monster issue," Dotcom said.

Meanwhile, tech news website CNET is reporting claims by Dotcom's American lawyer that US officials misled a judge when applying to seize Megaupload's domain names.

Silicon Valley attorney Ira Rothken said files recently released by a court showed US prosecutors had claimed Megaupload staff had failed to remove 30 pirated video files after being warned about them in June 2010.

However, Mr Rothken said the prosecutors had in fact told Megaupload not to interfere with the files so as not to jeopardise an ongoing investigation, CNET reported.