Megaupload founder Kim Dotcom is set to learn Wednesday if he will remain behind bars in New Zealand while US authorities seek his extradition on allegations of massive copyright theft.

The Internet tycoon has been in custody since police raided his Auckland mansion last Friday but vigorously denies any wrongdoing and has applied for bail as US moves to extradite him make their way through the courts.

Judge David McNaughton said on Monday that he would decide "at the very latest by Wednesday morning" whether Dotcom, also known as Kim Schmitz, must remain in custody.

Tuesday passed with no decision from the court.

The German businessman is among seven people indicted by the US Justice Department and FBI accused of "massive worldwide online piracy of numerous types of copyrighted works, through Megaupload.com" and other sites.

They allegedly generated more than $175 million in criminal proceeds and caused more than $500 million in harm to copyright owners by offering pirated copies of movies, TV programmes and other content.

Prosecutors opposed bail earlier this week, labelling Dotcom an "extreme" flight risk who had previously used his fortune to flee to Thailand when wanted on charges in Germany.

His lawyer, Paul Davison, argued that Dotcom had no intention of fleeing if granted bail as he wanted to stay in New Zealand with his pregnant wife and family.

Dotcom and three associates arrested with him in Auckland do not face charges in New Zealand and following the bail hearing, US authorities have 45 days to formally file extradition documents.

The other three people named in the US indictment remain at large.