Motorists will have new grounds to challenge speeding tickets after an investigation by National Nine News showed hundreds of defects in Sydney's fixed speed cameras.

A four month long National Nine News Investigation found that 568 faults had been discovered during 7,500 accuracy tests on the state's 117 fixed speed cameras.

The Roads Traffic Authority claims no motorist was wrongly fined as a result of the faults but speed camera lawyers say the never before released maintenance records will be used to launch new challenges to speeding tickets.

The RTA admits other faults, including flashes that didn't work, image quality issues and camera component problems, happened dozens of times and caused the review and possible withdrawal of speeding offences which had been detected.

"It shows we have a very rigorous testing regime," offered the RTA's Alec Brown.

"No maintenance issues led to any speed measurement errors in the last year."

But lawyer, Dennis Miralis, who makes a living fighting speed camera tickets, says it's the first time the RTA has publicly admitted maintenance issues could cause the withdrawal of speeding tickets.

"We are talking about tens of thousands of motorists who are affected by these sorts of problems — motorists which the RTA now are publicly acknowledging could lead to the improper issuing of a ticket and the consideration of the withdrawal of a ticket."

"These cameras are not invincible, these cameras are subject to error."

The investigation also found that the RTA doesn't routinely compile a list of the camera faults its inspectors discover.

Under Freedom of Information laws, National Nine News put in a request for three years of reports on the maintenance and accuracy of speed cameras. We were told by the RTA it would take a staff member 4 years to compile the information and cost $246,000.

The request was refused by the RTA's records access unit on the grounds it was an "unreasonable diversion of resources."