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

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," the German businessman, who changed his name from Kim Schmitz, said. "I have no desire to run away."

The decision means Dotcom 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 file-sharing website Megaupload.com has been detained since January 20 when New Zealand police, cooperating with a major US probe, raided his sprawling "Dotcom Mansion" in Auckland.

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.

During his court appearance, Dotcom also complained that he had received unwanted attention from female inmates wanting to become penpals while in custody, the New Zealand Herald reported.

It said Dotcom accused police of punching him during his arrest and also claimed he was visited by a man claiming to be a prosecutor who offered to ensure he was granted bail for a fee.

The black-clad millionaire, who spent his 38th birthday in a cell, said he wanted to remain in New Zealand with his family and regain the fortune that was seized when he was arrested.

"What I want to do is stay here to fight and get my money back," said Dotcom, who earned an estimated $42 million in 2010 alone.

The raid on Dotcom's home netted a 1959 pink Cadillac, numerous other luxury cars and valuable artworks -- all of which the US Justice Department and FBI allege was obtained through "massive worldwide online piracy".

Since his arrest, there has been a steady stream of media revelations about his extravagent lifestyle.

The Herald detailed claims he had a swimming pool filled with imported spring water, while a waitress who worked at the mansion told Women's Weekly magazine that fittings included gold toilet roll holders and silver plates.

And a documentary uploaded online shows Dotcom, surrounded by topless women, spraying champagne on board a superyacht during a "crazy weekend" in Monaco that reportedly cost $10 million.

"Fast cars, hot girls, superyachts and amazing parties. Decadence rules," said the blurb accompanying the documentary, which Dotcom dedicated to "all my fans".

The portly millionaire also reportedly had a butler in his mansion whose duties included retrieving stray ping pong balls when Dotcom was playing table tennis.

Dotcom paid for a NZ$500,000 (415,000) fireworks display in central Auckland on New Year's Eve 2010 and watched the extravaganza from a hovering helicopter, uploading the video on YouTube.

Prime Minister John Key said this week that since Dotcom's arrival in New Zealand in early 2010, his office had received complaints from the public about loud parties and cars speeding around the mansion, which is in his constituency.

Key said his staff had passed the complaints on to police.