A German interpreter has backed up an assertion by the defence in the Kim Dotcom case that an FBI translation of a message in which Mr Dotcom appears to call himself evil is inaccurate.

Photo: AFP

Mr Dotcom and three other men face extradition to the United States on charges of copyright violation, money-laundering and racketeering related to their website, Megaupload.

The hearing, under the jurisdiction of the North Shore District Court, is now in its seventh week.

Earlier in the case, the Crown lawyer Christine Gordon referred to Skype and email exchanges between the men that she said showed they knew what they were doing was illegal.

In one exchange, widely reported by media attending the extradition hearing, the Crown claimed Mr Dotcom said: "At some point a judge will be convinced about how evil we are and then we're in trouble."

What the Crown did not reveal in court was that the exchange was an FBI translation of the German original, Mr Dotcom's lawyer Ron Mansfield said.

When translated from German to English by three independent translators in New Zealand, the phrase was: "Because at some stage a judge will be talked into how bad we allegedly are and then it will be a mess".

Mr Mansfield said the US translation was inaccurate and an example of how unreliable the evidence against his client was.

A defence witness, Anita Goetthans, told the hearing she made an independent translation of the phrase and the US version contains several errors.

Ms Goetthans, who works as a freelance interpreter, said that included the translation of a word as "evil" that would be better translated as "bad".