The Pattullo Bridge, one of Metro Vancouver's busiest, has been closed to traffic since it was damaged by fire on Jan. 18. (CBC)

A key bridge serving the Metro Vancouver area, initially feared closed for four to six weeks, will re-open to traffic Monday morning, only one week after a small portion of it was destroyed by fire.

The Pattullo Bridge, which connects Surrey and New Westminster across the Fraser River and handles about 80,000 vehicles a day, will open at 6 a.m. for the Monday morning commute.

TransLink CEO Tom Prendergast said it wouldn't have opened early had it not been for construction materials intended for the Canada Line, the new rapid-transit artery linking downtown Vancouver to the airport. It was fortunate that officials were able to find a bridge structure that was basically dropped into place, he said.

The repairs were originally slated to take up to six weeks, before that was reduced to two and then to one.

"TransLink is extremely pleased to report that after a week of hardship to motorists and the travelling public at large, we will be able to open the Pattullo Bridge in time to handle Monday morning's rush-hour commute," Prendergast said Sunday.

The bridge was closed early last Sunday morning after a fire damaged a wooden trestle that supports the 72-year-old span's south end.

The closure created havoc for rush-hour commuters in Surrey, Delta and New Westminster, and jammed traffic on alternate routes across the Fraser River, including the George Massey Tunnel, the Alex Fraser Bridge and the Port Mann Bridge.

The cause of the fire has not been confirmed, but RCMP suspect the blaze was ignited by a campfire lit by a group of homeless people living under the bridge.

With files from the Canadian Press