Megaupload founder and internet piracy accused Kim Dotcom has released a new music video.

Exactly six months after his arrest following a police raid on his Coatesville mansion, north of Auckland, Dotcom released the song, Mr President, online on Friday evening.

In the track, Dotcom says, "The war for the internet has begun, Hollywood is in control of politics, the government is killing innovation, don't let them get away with that".

US authorities are trying to extradite Dotcom and three others to face racketeering, copyright and money laundering charges relating to the Megaupload website.

They face up to 20 years in prison if convicted.

The four were arrested in New Zealand in January in a joint operation by New Zealand authorities and the FBI.

Late last month, a High Court ruling declared the armed police raid on Dotcom's Coatesville mansion in January illegal.

Justice Helen Winkelmann said the search warrants used were too broad and police exceeded their powers in seizing what they did.

She also said it was unlawful for copies of Dotcom's computer files to be taken by US authorities and New Zealand police should return copies to 38-year-old Dotcom.

Lawyer John Pike, acting on behalf of the US government, has indicated he may appeal Justice Winkelmann's ruling.

Prosecutors acting on behalf of the US government have also appealed a District Court ruling that Dotcom and his co-accused must be granted access to the evidence held against them for the extradition hearing.

The outcome of that appeal is still unknown.

Earlier this week, the Judge David Harvey, who was due to hear Dotcom's extradition case in the District Court, stepped down after he referred to the US as "the enemy" during an internet conference discussion on copyright laws.