The Australian man who claims to have invented bitcoin a decade ago submitted false documents and lied in a legal dispute with the estate of his former partner, a judge ruled, adding that Craig Wright has to surrender more than $US4 billion ($5.9 billion) of the cryptocurrency.

Australian Craig Wright claims to have invented bitcoin. Credit:AP

US magistrate Judge Bruce Reinhart in Florida ruled on Monday that the late Dave Kleiman owned half of all bitcoins that Mr Wright mined through to 2013, and half of all intellectual property he created, according to a court transcript. That would give title to more than 410,000 bitcoins to Kleiman's estate. One bitcoin was worth $US10,162 on Tuesday.

Judge Reinhart issued the ruling in sanctioning Mr Wright for failing to comply with orders to turn over documents in the Kleiman estate's lawsuit in which it claimed Mr Wright illegally seized the assets and for lying.

The ultimate test may be whether Mr Wright is actually able to deliver the bitcoins to Kleiman's estate. In his testimony Mr Wright said he doesn't know where all the bitcoins are and may not even be able to access them. Any sale or transfer of the huge stake of coins could dramatically affect the bitcoin price.