Recent law reforms have made it easier for both state and federal police to seize  unexplained wealth, removing the need to prove assets are linked to criminal activity.

The High Court's decision, however, could delay them from seizing both proceeds of crime and unexplained wealth when there is a related criminal trial, even when the property belongs to someone who is not charged with a crime.

Xing Jin is part of a family syndicate which allegedly illegally managed more than 100 sex workers in brothels across Melbourne. The day he was charged with aiding and abetting dealing in at least $100,000 of illegal sex workers' earnings in July 2013, he was also restrained from selling his Southbank property and a car owned by his company.

His wife, Qing Zhao, who is not charged, was also restrained from selling their Donvale family home. The properties alone are believed to be worth more than $1 million.

Jin successfully argued in the Victorian Court of Appeal that they should not be seized until after the charges – which he denies – are determined after his criminal trial in August. If police began court proceedings for a forfeiture order, he said he would be forced to testify how he came to buy the properties, which was directly relevant to the criminal charges against him.

"If I am to depose these matters in an affidavit in the proceedings I will, in effect [be] waiving my right to silence. I do not wish to do so," he said in court documents.

The High Court unanimously dismissed an appeal from the Australian Federal Police earlier this month, blocking it from forfeiting the property of Jin and his wife Qing Zhao, who has not been charged.

The decision is likely to stall 43 other cases where police have applied to seize  proceeds of crime ahead of criminal trials.

"All or a majority of any applications for stays of those proceedings would be granted, thereby severely delaying and impeding the ability of the Commissioner to carry out his duties, powers and functions as a proceeds of crime authority pursuant to the Proceeds of Crime Act," the manager of AFP's proceeds of crime litigation, David Gray, said in court documents.

The cases included Jin's mother, Moon Ja Kim, who is also charged with aiding and abetting, and a man charged with drug offences in South Australia.

Chief Justice Robert French and Justices Kenneth Hayne, Susan Kiefel, Virginia Bell and Patrick Keane said there was a real risk of prejudice to Jin's criminal case if they they did not stall the civil forfeiture proceedings, "given that the offences and the circumstances relevant to both proceedings are substantially identical".

The judges said Jin did not need to explain why it would prejudice his case because this would force him to "reveal information about his defence, the very situation which an order for a stay seeks to avoid."

David Neal, SC, for the Australian Federal Police, said alleged offenders will now be able to stall the police from seizing  proceeds of crime for years if they say there is a "substantial overlap" between the civil and criminal proceedings: "The prospect that forfeiture proceedings will go ahead in advance of the criminal trial is virtually nil."

Forfeiture orders were an important tool to deter people from committing organised crime, he said. "The financial incentive that drives them is [now] removed or lessened. These crimes are money crimes, so people who are doing these sorts of things are calculating how much money they can make from it."

A spokeswoman for Federal Justice Minister Michael Keenan did not answer questions about whether the decision undermined recent reforms or whether he would consider further changes to the law.

She said the Coalition was aware of the High Court's decision. "Combating serious and organised crime is a national priority. The Coalition government is determined to ensure we have the right arrangements in place to strip criminals of unexplained wealth and make Australia a safer place."