Kim Dotcom's assets will be within reach of the United States before the entrepreneur's extradition process is completed.
A Court of Appeal decision, released today, means millions of dollars, several luxury cars, jewellery and other property remain frozen.
The ruling is also a blow for Mona Dotcom, who is now separated from Dotcom and unsuccessfully applied for her property to be excluded from the order.
Ms Dotcom had argued that she had not been charged with any offence and had no knowledge that any property was the proceeds of criminal activity.
The US government's attempts to have Kim Dotcom extradited to face trial on copyright infringement, money laundering and racketeering charges relating to file-sharing website Megaupload have been delayed by numerous court battles.
He has not been able to access the assets because of a foreign restraining order made at the time of his high-profile arrest in Coatesville in January 2012.
The order expired in April and the High Court turned down a police application to extend it.
That decision was appealed, and today's decision quashes it and extends the restraining order until April next year.
The orders were originally made using a criminal process that would mean Dotcom's assets wouldn't be forfeited until there was a conviction in the case in the US.
Authorities then decided to use a different, civil process that would mean the assets would be within reach before the completion of Dotcom and his co-accused Bram van der Kolk's extradition process.
Dotcom's lawyer Robert Gapes argued that change of grounds was unfair and should not be allowed under the law.
However, today's decision found that it was appropriate to extend the order and the switch to civil forfeiture was not significant.
"The evidence before the Court is that forfeiture proceedings of a kind contemplated by the US restraining orders can be completed before April 2015," stated the judgment, which was delivered by Justice Mark O'Regan, president, Justice John Wild and Justice Christine French.
Dotcom has been travelling the country in his role as founder of the Internet Party.