Officials are apologizing to an injured mother and daughter who were left to wait four hours for an ambulance in the Metro Vancouver area on Monday, in an incident critics say highlights the need for more ambulances in the province.

The pair suffered non-life threatening injuries in a car crash in Surrey, B.C., and were forced to wait by the intersection with firefighters as they were repeatedly passed over in ambulance triage. At least 10 ambulances were dispatched to treat them, only to be diverted to higher-priority calls, according to Linda Lupini, vice president of B.C. Emergency Health Services.

"We're very apologetic," Lupini said, adding that B.C. EHS has immediately introduced an interim escalation policy to deal with incidents like this one.

But Bronwyn Barter, president of the Ambulance Paramedics of B.C., says more ambulances are needed to address the issue.

"This is one example of many," she said of Surrey incident. "This is happening on a day-to-day basis and it's very concerning."

The provincial government has added nine ambulances to the Metro Vancouver area so far this year, but a government report published earlier this year suggests 13 more are needed to meet the region's needs.

"We can't wait any longer," Barter said, adding that the issue could fixed "overnight" with additional funding. "The patients can't wait. People are going to die."

Lupini says the B.C. EHS would welcome more resources, but the overall problem is "more complicated" than the number of ambulances available.

With files from CTV Vancouver