Two of Kim Dotcom's co-accused were granted bail in New Zealand Thursday, a day after the Megaupload boss was ordered to remain behind bars pending US attempts to extradite him for copyright piracy.

Judge David McNaughton, who denied Dotcom bail after deeming the Internet tycoon a serious flight risk, said he was prepared to release co-accused Finn Batato and Bram van der Kolk subject to strict conditions.

He reserved until Friday a decision on bail for Mathias Ortmann, a fourth Megaupload executive arrested last week in a raid on the sprawling "Dotcom Mansion" in Auckland.

McNaughton said Dutchman van der Kolk, Megaupload's chief programmer, was in a different position to Dotcom, who legally changed his name from Kim Schmitz and has numerous bank accounts.

"There is no issue in Mr. van der Kolk's case of multiple identity or multiple passports, no connection to any firearms and... (no evidence) of access to any other funds," he said in a written decision.

The judge said the evidence suggested Batato, a German national, was "a man of good character" who was unlikely to attempt to flee New Zealand.

Lawyers for Dotcom, who vigorously denies any wrongdoing, have said they will appeal this week's decision to keep him in custody while US authorities seek his extradition for "massive worldwide online piracy".

The US Justice Department and FBI last week alleged Megaupload and associated sites generated more than $175 million in criminal proceeds and cost copyright owners $500 million-plus by offering pirated content.