The Police Service of Northern Ireland (PSNI) is facing a staffing crisis after more than three-quarters of its officers voted against a change in shift patterns.
The service is proposing to change its current set-up of 12-hour shifts for four consecutive days to a variable eight-to-10-hour shift pattern on 31 March. But the Police Federation for Northern Ireland, which represents 9,000 rank and file officers, said the service must reconsider its decision.
Terry Spence, chairman of the federation, said: "Some officers could seriously consider resigning if the shift change is pushed through and the service might not be able to meet the staffing requirements. The force is risking a very disgruntled workforce.
"I want to call on the chief constable to have a meaningful consultation with us. Let's have a clean slate and look at this again."
The new variable shift pattern is unpopular with officers because it offers a poorer work-life balance than the alternative four days on, four days off, Spence said.
But the PSNI remained defiant. "The current 12-hour shift pattern is ending on 31 March. It is expensive, inflexible, and does not take account of the peaks and troughs of demands," a spokeswoman said.
The working arrangements were being changed because police were "committed to providing the people of Northern Ireland with the best possible policing service", she added.
It is unlawful for police officers across the UK to go on strike under the Police Act of 1919.