The B.C. Ambulance Service says over 50 paramedics booked off their scheduled shifts just before they were to start work Saturday during an escalating labour dispute.

Spokeswoman Chris Harbord says that left a total of 23 ambulances out of service in the Lower Mainland, the Fraser Valley and the Sea-to-Sky corridor.

She says 103 ambulances normally service that area on the day shift.

Harbord says there were no ambulances staffed in Boston Bar, Hope, Agassiz or Pemberton and only one ambulance in Mission and Whistler.

She says the ambulance service is moving ambulances from the Interior and re-assigning ambulances throughout the Lower Mainland.

In addition, a doctor is working with emergency dispatchers to ensure patients are properly prioritized while the ambulance service is urging people to call 911 only for critical illnesses and injuries.

B.C.'s paramedics have been on strike since April 1, when they began working under essential services orders.

Last weekend, the B.C. government pushed through a bill ordering the province's 3,500 paramedics back to work.

Health Minister Kevin Falcon said at the time that the seven-month strike was putting people's health at risk with the approach of winter and concerns about 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.