The B.C. Ambulance Service urged residents of the Fraser Valley and Lower Mainland not to call 911 Friday evening unless in a true medical emergency after a number of paramedics booked off their shifts just as they were getting set to begin.

B.C. Ambulance said the number of ambulances operating in the Fraser Valley Friday night went from the scheduled 15 all the way down to two.

In the Sea-to-Sky corridor, four out of the eight ambulances didn't hit the road and in Metro Vancouver another seven were tagged out of service.

The provincial government introduced legislation earlier this month that ended a paramedic strike that had gone on since April. The Liberal government's move was blasted by union leaders.

Les Fisher, executive director with B.C. Ambulance Service, said it's very strange that so many paramedics cancelled their shifts just as they were about to begin.

"To have this number out is very unusual," he said.

"We had all the shifts covered earlier (Friday). And just prior to the shift start time a number of staff called their unit chief and advised that they were no longer available to work or that they were sick or any number of reasons that they came up with."

B.C. Ambulance advised the public that service for low priority calls would likely be delayed, but Fisher said emergency calls would be handled on a priority basis.

Those suffering from minor injuries or illnesses were instead asked to visit a local walk-in centre or call the province's HealthLink number.

Fisher said B.C. Ambulance was forced to call in ambulances from the Interior and reassigned them throughout the Lower Mainland.

BJ Chute, a spokesman for paramedic union CUPE Local 873, said the staffing shortages were not part of a concerted effort.

"If the Ambulance Service did believe that, or had any sort of proof whatsoever that this was illegal action, they would be taking us either to the Labour Relations Board or to the courts," he said.

Members of the B.C. legislature pushed through a bill ordering the province's 3,500 paramedics back to work earlier this month.

Health Minister Kevin Falcon said at the time that the strike had dragged on too long and was putting people's health at risk with the approach of winter and the danger of the H1N1 virus.

Paramedics disputed that claim and said there was no need for the government to force a contract on the union.

The retroactive one-year contract gave the paramedics a three-per-cent wage hike.

Throughout the strike the paramedics had been working under Essential Services orders, and other than a giant sticker reading "On Strike" pasted on ambulances, the public noticed little difference in service.

Falcon did not return a call seeking comment.