The delay is because of questions about the search and seizure of evidence by the United States where he faces charges of Internet piracy and fraud.

William Akel, one of Dotcom’s lawyers, said on Tuesday a hearing scheduled for August has now been postponed to a tentative date of March 25 because two judicial reviews regarding illegal search warrants and evidence disclosure are still underway.

“It was inevitable that the hearing for August was going to be vacated because we have two existing cases in the High Court,” Akel told Reuters.

In its highest-profile investigation into online piracy, the US Federal Bureau of Investigation alleges that Dotcom, also known as Kim Schmitz, led a group that has netted $175 million since 2005 by copying and distributing music, movies and other copyrighted content without authorisation.

Dotcom’s lawyers say the company simply offered online storage.

The extradition hearing delay follows the New Zealand High Court’s ruling in June that search warrants used by police to search the flamboyant Dotcom’s house to collect evidence were illegal. The court also ruled that copying the evidence by the FBI and sending it to the United States was also unlawful.

Dotcom’s lawyers and the prosecution are awaiting a decision on how to handle evidence obtained under the illegal warrants and whether evidence to be used in the US criminal case will be disclosed to the defence team at the extradition hearing.

Akel said he was “disappointed” about the delay.

“You obviously want the extradition case to go ahead as soon as you can, but you have to put up with the inevitable,” he said.

Acting on a request from the FBI, New Zealand armed police, backed by helicopters, swept into the 38-year-old Dotcom’s rented estate outside Auckland in January, confiscating computers and hard drives. Dotcom and three others were arrested.

Dotcom was originally denied bail after the raid and jailed for a month, but the courts have progressively eased restrictions on him, allowing him back into his mansion, giving him access to hundreds of thousands of dollars for living and legal expenses and removing some travel and meeting restrictions.