The state's crime watchdog has “expressed concern” over an increase in police officers shooting at moving vehicles.

The Crime and Misconduct Commission wrote to the Queensland police commissioner after investigating “significant events” where firearms had been discharged during the 2011-12 financial year.

The commission reviewed each incident, examined the justification of the officer's actions and scrutinised the resulting investigation by the Ethical Standards Command.

However, a CMC spokeswoman told Fairfax Media on Wednesday that it would not provide further details of its review of the shootings, including the number of shootings that were considered to be in breach of QPS policy.

Overall, there were 5240 allegations made against police to the CMC last financial year, a drop of 15 per cent from 2011-12.