The lawyer for Kim Dotcom says a Supreme Court ruling may harm the internet businessman's chance of getting a fair extradition hearing - but it's not game over yet.

Mr Dotcom, a German national with New Zealand residency, is fighting extradition to the United States where he and three colleagues face charges in connection with one of the world's biggest internet copyright cases.

Photo: RNZ

The Supreme Court on Friday dismissed Mr Dotcom's bid to access more FBI evidence against him, ruling that he is only entitled to a summary of evidence.

Lead lawyer Paul Davison, QC, said Mr Dotcom needs the full evidence to prepare for the extradition hearing in July this year and there may be other ways to get that.

"We also have the opportunity of pursuing under the Official Information Act any information held by the New Zealand agencies, which they may in the end have received some of the material from the United States as well. So anything held by the New Zealand agencies may well be susceptible to being disclosed to Mr Dotcom.

"There are a number of things that we will continue to do and although this is a setback, it's certainly not game over."

Mr Davison told Radio New Zealand's Checkpoint programme the summary cherry-picks from a huge range of email, telephone and Skype conversations.

"If he is unable to present these communications in context, then he will not be able to get a fair hearing because he needs access to that material in order to do that. And that's exactly why we are pursuing this."

Mr Dotcom is facing copyright and money-laundering charges and took to the social media network Twitter on Friday morning after receiving the judgement, tweeting a sad face symbol.

US has met obligations - Supreme Court

The Court of Appeal had ruled that the US only had to give Kim Dotcom's legal team a 109-page summary of the evidence against him.

However, his lawyers argued in a hearing in July 2013 that the summary was inadequate and drew conclusions without providing any of the relevant background material.

In the majority ruling released on Friday, the Supreme Court turned down that appeal, saying the Extradition Act does not require the US to supply copies of all documents that the summary refers to.

The court says the US has a duty of good faith to disclose any evidence that would undermine its case against Mr Dotcom, but it says there's no suggestion that the US has not met those obligations.

The Supreme Court also found that the District Court that originally ordered the documents should be disclosed didn't have the power to make that order.

Chief Justice Sian Elias disagreed with her Supreme Court colleagues.

Dame Sian says the "record of case" that the US has to provide must include both a summary of the evidence and the documents, such as emails, that the summary refers to.

She says even if that didn't apply, the District Court still has the authority to order the US to disclose documents that they're relying on to establish an initial case.

Read the full Supreme Court decision