Traffic tie-ups are about to get worse for commuters trying to get in or out of Montreal's downtown core.

Lanes will be closed indefinitely on both the east- and the west-bound sides of the Ville-Marie Expressway, which is used by millions of commuters every day.

Transport Quebec officials held a hasty news conference late in the day Thursday to deliver the bad news.

In a report filed earlier in the day, engineers said much of the expressway needs to be repaired — immediately.

Transport Quebec spokesman Mario Saint-Pierre said it's still unclear how long the work will take.

"We will begin shortly, and it's going to last for — we don't know yet. It's going to need some time. It's more major repairs than a quick fix."

These closures come on top of problems announced several weeks ago when some lanes were closed while crews repaired cracks in a support pillar. Those lanes are still closed.

Now, in addition, the left-hand lane in both east and west directions will be closed while crumbling concrete is repaired. East-bound, the closure is from Atwater Avenue to Guy Street. West-bound, it's from Panet Street to Saint Jacques Street — a full five kilometres.

Transport Quebec's Montreal project manager, Claude Paquette, admits there have been a lot of lane restrictions in the past few months

But, he said, in the wake of last year's Concorde overpass collapse that killed five people, inspectors are taking no chances when it comes to the safety of Quebec's aging roadways.