Drug exhibits are being held by NSW police for too long, jeopardising the health and safety of officers and creating high storage costs, an audit has found.

Police resources are also being tied up as drug exhibits and samples are moved around the state, NSW Auditor-General Peter Achterstraat says.

"We estimate these trips take police officers away from frontline duties for the equivalent of 2000 days each year," he said.

"Drug exhibit samples are not entirely used up in testing and the remainder has to be collected and returned to police storage facilities, creating additional administration and transport costs."

The audit, handed to NSW parliament on Thursday, found police collected 313,000 exhibits and other goods in 2011-12.

About 58,000 were drug exhibits and goods such as cars, boats and guns.

Of these, 60 per cent were held for longer than six months.

More than 3600 drug exhibits and other high profile goods had been held for more than two years.

Police in NSW are currently required to hold on to some drug exhibits until a court order is obtained for their destruction.

But they are looking to adopt the practices in other jurisdictions, where the drugs are destroyed without a court order as soon as they are independently analysed.

Mr Achterstraat backs the move.

"The practices used in other jurisdictions reduce the risks to officers' health and safety," he said.

However, he said the drug exhibits were well managed, securely kept and routinely audited.

"There are few recorded instances where they have gone missing or been damaged," he said.

The report calls on NSW police to review all drug exhibits and other high profile goods on hand for more than two years and dispose of any no longer required.