Almost one in 10 mobile speed camera fines cannot be issued, with illegible and obstructed number plates helping motorists dodge tickets.

But motorists are warned not to be complacent, with the Queensland Police Service upgrading all cameras from analogue to digital, resulting in a boost in accuracy.

The rollout of digital mobile speed cameras has resulted in a 16 per cent increase in offences detected resulting in notices issued.

From June 2015 to April 2016, there was a 16 per cent increase in the number of offences detected in the mobile speed camera program resulting in notices issued.

As of April 2016, the percentage of detected offences resulting in notices issued under the program was 91.44 per cent.