Roads Minister Duncan Gay instructed the RTA to immediately turn off the "ineffective" cameras at 38 of the state's 141 fixed-camera sites, including Newcastle Road, Lambton, and the New England Highway at Scone and Murrurundi, in line with the Coalition's promise to get rid of cash-cow cameras.

The move went further than recommendations in a new report from NSW Auditor General Peter Achterstraat that support be given to the RTA's plans to move the 38 cameras after further review.

It was also despite Mr Achterstraat's comments that removing cameras without implementing other measures could send the wrong signal.

' ' . . . ripping out a speed camera also sends a message to hoon boy Harry that he can go as fast as he likes at that spot," Mr Achterstraat said.

The audit found overall crashes and injuries each fell 26 per cent, and fatalities fell by more than two-thirds in the three years after the installation of fixed speed cameras.

But while the RTA had assessed 93 of the cameras as having a clear road safety benefit, the audit could only confirm that 40 had led to statistically significant reductions in crashes and that more data was needed.

However, there was no evidence the cameras were positioned as revenue raisers.

The cameras had raised an average $10 million a year over their life and Mr Gay did not rule out using them elsewhere if they were needed on safety grounds, but said they would be removed from their current spots within weeks. He said mobile speed cameras were still operating.

NRMA Hunter director Kyle Loades backed the cameras' removal and Mr Achterstraat's recommendation for an annual review of each camera.

"The new roads agency replacing the RTA needs to be much more responsive to motorists' concerns," Mr Loades said.

Mr Achterstraat said more information about crash statistics should be made public so people could see the benefits.