audit of NSW's speed cameras will be carried out to determine if they really are having an impact on road safety.

I'll rip out cash cow cameras: O'Farrell
An audit of NSW's speed cameras will be carried out to determine if they really are having an impact on road safety.

An audit of NSW's speed cameras will be carried out to determine if they really are having an impact on road safety.

If they are not, NSW Premier Barry O'Farrell says, "They will be ripped out".

O'Farrell on Thursday said each of the 172 fixed, six mobile and 60 safety cameras would be investigated in the auditor-general's review

The audit was needed to address motorists' concerns the cameras had become mere cash cows under the previous government, rather than used to improve road safety, he said.

While the premier admitted the unpopular devices were useful in curbing driver misbehaviour, he promised to rip out any camera used merely to gouge money out of NSW motorists.

"Fixed cameras can be useful, there is no doubt about that. Red-light cameras can be useful," O'Farrell told reporters at the RTA's Traffic Management Centre in Sydney.

"What we want to make sure is that transparently, openly, there is an audit to ensure motorists know whether or not cameras at certain locations are delivering that better road safety outcome, or whether it is just in fact about revenue raising."

O'Farrell said at the very least the audit, expected to take about three months, would "remove scepticism and cynicism about this issue".

"At best it will demonstrate case by case whether these cameras are achieving their outcome," he said.

The audit "ticked off" on another election promise of the new government, O'Farrell said.

Motoring group the NRMA applauded the audit, saying motorists had to be assured cameras were only used in spots that would make roads safer.