Ms Fenton said police had told her in written answers that police vehicle numbers had fallen by 157 with road policing vehicles contributing most to the reduction, falling from 763 to 690.
Ms Fenton said it was no wonder the road toll started rising last year.
"When the cut in the number of road policing vehicles is seen in tandem with the $50 million over three years National slashed from traffic policing in last year's budget, it's even harder to be optimistic (that the road toll will come down)," Ms Fenton said.
Other police vehicle reductions were made in the areas of CIB, administration, general duties and specialist vehicles.
Last year former deputy commissioner Lynn Provost said a 10% cut in vehicles would save $2.4 million without compromising service as part of a drive to cut $21 million from the police's $1.5 billion budget.
