WA Police officers will face an uncertain future if they are unable to pass a new annual fitness test designed to ensure they are capable of frontline duties.

Commissioner Karl O'Callaghan has announced that the test will be mandatory for all operational officers from January.

He is yet to decide what the consequences will be for those who repeatedly fail the test.

The Police Union said yesterday that while it agreed operational officers needed to be fit, it was concerned the test might be used to force those injured in the line of duty "on to the scrap heap". "The agency has an obligation to ensure their employees are looked after should they suffer an injury which immobilises them and renders them non-operational," union president George Tilbury said.

Mr O'Callaghan said officers already considered unfit for frontline duty because of long-term injuries or health problems would not be in the firing line of the new policy. He could not say what would happen to officers who were injured in the future.

"There are legacy issues where there are officers who have been non-operational for a long time and are being managed but you can't go to them and tell them to do the course," Mr O'Callaghan said. "We have accepted them as they are. This is about preparing the agency for the future."

Reforms to the police service have resulted in a number of administrative positions that used to be filled by officers now being handled by public servants. It means there are fewer places for injured officers to work away from the front line.

"The public of WA are entitled to feel that as many officers who are employed by WA Police as possible are actually on the street," Mr O'Callaghan said.

"Like every occupational requirement, there eventually must be a consequence if standards cannot be met. This consequence will be addressed over the first 12 months of this pilot."

The test is modelled on those used by police in Canada, Queensland and Victoria and attempts to replicate scenarios officers could face. Figures from other States indicate that about 2 per cent of officers fail the test.

The course starts with a 200m "foot chase" - four laps of an obstacle course that tests an officer's agility and ability to climb a 1.5m fence, jump knee-high hurdles, clear a 1.5m ditch and run up stairs. The officers must then "take down" a 40kg weight to replicate subduing an offender, handcuff a dummy and carry a 35kg load. There will be no time limit for the first year of testing but officers will have to complete the course without stopping.

"A key issue for me is that if you are a fully trained, fully operational officer and you're working with someone who is not, that is a significant concern," Mr O'Callaghan said.

He said there had been resistance to the assessment because of the questions about the consequences for those who did not pass.

Mr O'Callaghan said officers who failed the test the first time would be given fitness, strength or nutritional guidance to improve and retested three months later. Police who failed again would temporarily lose their operational status and their commanding officer would decide if there was an office-based role they could do or if they would have to find another position.

They would then be managed under a health and welfare system.

Currently, there are no continuing fitness tests once officers have graduated from the WA Police Academy.