Kim Dotcom's lawyers intend to ask the German government to intervene with the United States and try to block his extradition on criminal copyright charges, German news agency DPA has reported.

London-based Canadian human rights lawyer Robert Amsterdam, who co-wrote a "white paper" released last week criticising the case against Dotcom's MegaUpload business, told the DPA that Germany had not done enough to assist Dotcom.

He said he would ask the German government to intervene on the grounds that Dotcom's human rights had been violated by the US.

"We can take this to the office of the Chancellor, which we will, as well as to the German Foreign Ministry, to raise the issue with Washington," he told the DPA.

"He is a German citizen, aside from being a New Zealand resident. It is a German citizen whose rights have been so abrogated, and there are obligations under the German constitution."

Germany had "every reason" to advocate on Dotcom's behalf, Amsterdam said. "We have established a strong case that this is a political prosecution and when you match that with the admitted illegality of what went on in the raid . . . I think it makes a very powerful argument."

Amsterdam said he also intended to approach an international organisation to lodge complaints about the US' treatment of Dotcom.

- The Dominion Post