Fleet owners that fail to maintain their vehicles or ignore mechanics' advice on necessary repairs could be prosecuted under new police procedures, a fleet expert has warned.

Amery Parkes solicitor David Faithful said the Association of Chief Police Officers had produced a manual on road death investigation.

This instructs police to check the mechanical condition of occupational vehicles that are involved in accidents.

"The police will want to see maintenance records and know the daily or weekly checks carried out as to roadworthiness," he said.

Faithful said if an expert has advised the fleet operator of any necessary repairs, and that advice is ignored, the operator could face criminal proceedings.

"If fleet technicians make a recommendation to a person in authority, who then makes a conscious decision not to follow the advice, any liability following an accident will fall on the employer of the person making the decision," he said.