The laws would replace those used by intelligence agencies such as the Australian and NSW crime commissions, which have the power to seize assets but only through criminal proceedings that require investigators to link the funds to specific crimes.

The legislation, used by Italy's Mafia investigators in recent years, will be included in a series of recommendations to be released later this year from a parliamentary committee into organised crime.

Under the planned legislation, senior organised criminals would be forced to explain their wealth in civil proceedings and, unless a legitimate explanation could be provided, assets would be seized.

Vice President of the NSW Council for Civil Liberties David Bernie told Lawyers Weekly that the organisation was concerned that the new laws would mean people might lose their property - even when they hadn't been charged or convicted of a criminal offence.

"Also this will be done on the balance of probabilities rather than the normal criminal onus of 'beyond a reasonable doubt'. Indeed, it appears that the main purpose of the new amendments is to actually shift the onus onto the person to show how they came by their wealth, rather than the other way around," he said.

"So really it reverses the onus of proof, so you're presumed guilty."

Labor Senator and committee chair of the parliamentary committee Steve Hutchins acknowledged the laws would need to be written so they did not target legitimately earned assets, but said he believed they were a simple way of halting organised crime.

"There needs to be checks and balances, but in the end we know there are people in Australia driving Rolls-Royces but with no visible means of support," he said.

"They have the best of lifestyles, live in multimillion-dollar mansions, and they're known as promotions managers at nightclubs. We're not idiots - and we're not going to put up with it any more."

But Bernie argued that there was already plenty of power under existing proceeds of crime legislation to confiscate assets acquired through illegal purposes.

"What this is about really is lazy police work. In other words, 'We don't have enough criminal intelligence, we don't have enough evidence to actually prove our case so we're going to turn around and make you prove that you're not guilty'," he said.

Bernie said the recent bikie-related violence in NSW was one reason assets from organised crime were being targeted.

"I think it's also because of the publicity in NSW in regards to certain people who appear to be earning nothing but have this lavish lifestyle and there is speculation that it's through illegal drugs. It seems to me, if that is the case, then somebody should be prosecuted for supply and then it's quite legal to then trace assets and the profits of that supply," he said.

"The government can seek to get that money back and have that forfeited to the Crown. That's always been the case. The real concern here is that if the government points the finger at you, the onus is on you to actually show how you got the money. It's a complete reversal of what we understand is our system of justice."

The NSW Police Association supports the proposals and wants the State Government to adopt a similar model to Northern Territory and Western Australia laws which have seized more than $40 million in alleged criminal assets since 2003.

"These laws focus on the Mr Bigs who are often at arm's length from the crimes - not the functionaries at the bottom and in the middle that get caught," said the president of the NSW Police Association Bob Pritchard.

- Sarah Sharples