It would cost Kim Dotcom about US$500,000 to get the US experts he needed to rebut efforts to extradite him, a court has heard.

The internet entrepreneur's extradition hearing has been effectively paused, after the US government detailed its case, while defence lawyers make various arguments for a stay of proceedings.

Counsel for the US government Christine Gordon, QC, opened the case by calling it a "simple scheme of fraud" where users of the Mega websites widely shared copyright-protected material under the noses of those running the company.

The FBI laid charges in January 2012 when the German mogul and three others - Mathias Ortmann, Bram van der Kolk and Finn Batato - were indicted on 13 charges including copyright infringement, racketeering, money laundering and fraud.

Dotcom's US attorney Ira Rothken was called to give evidence today and was asked by defence counsel Ron Mansfield to detail the type of overseas experts needed to properly oppose the extradition.

Mr Mansfield is arguing there should be a stay of proceedings because the Crown - on behalf of the US government - adopted a "starve out" policy which restricted Dotcom's funds being used to recruit US technical and legal scholars to help his case.

Mr Rothken said they would need about US$500,000 to get the people they needed and it could take up to six months to gather all the evidence required from them.

Trying to find experts to contribute for free had been "futile", he said.

"With the complexity of this case and the time and effort for travel, that's the reality," said Mr Rothken.

However, one high-profile figure had agreed to help.

Professor Lawrence Lessig - a world-renowned copyright expert currently running for president - had provided an affidavit outlining his views on the case.

His attempts to replace Barack Obama at the helm of the most powerful country in the world might make his appearance before a New Zealand court difficult, Mr Mansfield said.

Mr Rothken said the defence would also engage technical experts who could look at the metadata taken from Mega servers.

The Crown told Judge Nevin Dawson there had been 10,000 take-down notices made to Dotcom's website which were ignored but Mr Rothken said they had neglected to mention 10 million that had been complied with.

"The expert will say that's over 99.99% compliant and not a prima facie case as a matter of law," he said.

Dotcom is expected to give evidence after Mr Rothken.

The hearing continues.