Opposition MP Clayton Cosgrove says police call outs are being delayed as some officers wait up to three hours for vehicles to be returned by officers on other jobs.
At a Select Committee hearing of the Police financial review, Labour's law and order spokesperson told Police Commissioner Howard Broad he knows of cases where officers arriving on shift are left with nothing to because they do not have any transport.
Mr Broad says the force managed to make $21 million in budget savings last financial year by asking staff to take extra leave, cutting travel expenses and consultant costs.
Its fleet of 3500 cars has been reduced by almost 300.
Mr Broad acknowledged that sometimes officers who are using cars "keep the keys in their pockets", which he says needs to be dealt with at a district level.
Mr Broad says officers have told him they can cope with the reduction in vehicles, but he is willing to take a further look at individual cases.