Megaupload boss Kim Dotcom has failed to overturn a ruling that he remain behind bars in New Zealand while US officials seek his extradition for alleged copyright piracy, according to reports.

Dotcom appeared in the Auckland High Court to appeal a judge's refusal last week to grant bail because he had the wealth and connections to slip out of the country.

The appeal was rejected after lawyers representing US authorities told the court a man with a history of producing fraudulent travel documents unsuccessfully applied to visit Dotcom while in custody, TVNZ reported.

Dotcom denied any knowledge of the man and said he was not friends with him, Fairfax Media reported.

"If people were to approach me and to offer such a service, I would tell them to go to hell," he said. "I have no desire to run away."

The decision means Dotcom, who changed his name from Kim Schmitz, will remain in prison until at least February 22, when a US application to extradite him is scheduled to be lodged in court.

The founder of the file-sharing website has been in detention since New Zealand police, cooperating with a major US probe, raided his sprawling "Dotcom Mansion" in Auckland on January 20.

The US Justice Department and FBI allege Megaupload and related sites netted more than $175 million in criminal proceeds and cost copyright owners over $500 million by offering pirated copies of movies, TV shows and other content.