The number of speeding tickets issued to motorists in the first six months of this year is down nearly 53,000 on the same period in 2008. Faulty new mobile cameras are partly to blame.
Film cameras have been replaced with digital systems and police say there have been minor technical issues to fix.
There was some downtime during the transition, as 31 existing cameras were replaced with 43 new models.
Data on the the value of fines has not been collated. But based on the minimum automatic fine of $80, more than $4.2 million of revenue has been lost.
Police say there is no pressure on them to increase ticket numbers as a measure of success.