Emergency vehicles are lined up around Portage & Main in downtown Winnipeg after a gas leak caused by a construction worker.

Manitoba Hydro crews were called to the area around noon today.

Manitoba Hydro spokesperson Scott Powell said that it appears that a contractor damaged a gas main on Fort Street just south of Portage Avenue.

"The gas right now is venting to the atmosphere, which is good," Powell said shortly after the incident.

"It's not migrating underground into the sewers or anything like that."

Thousands of people were forced out of buildings in the area including the Royal Bank Building at 360 Main St., 230 Portage Ave.,  as well as the underground mall, Winnipeg Square.

Manitoba Hydro says that the gas in the area had been shut off as of 1:30 p.m. and repairs were beginning. Hydro was also going room to room in affected buildings to ensure all was well.

Traffic was closed for southbound Main from Portage to Graham. That has since been reopened, but as of 2:00 p.m. emergency vehicles remain in the right-hand lane of southbound Main St. between Portage and Fort.

Update - 2:30 p.m.

Manitoba Hydro says that 45 downtown customers are currently without natural gas.

They say that the expect crews to remain on Fort St. for some time while repairs are carried out.

The City of Winnipeg says that crews are allowing a staggered reentry into buildings so people can gather personal belongings and leave parkades. 

The City is asking for patience as it's expected to take a while to let everybody back in, and then leave the area.