A plan to dump 8 billion litres of untreated sewage into the St. Lawrence River is being put on hold.

The sewage was going to be flowing into the river for seven to ten days, beginning Oct. 18, because of construction work being done on the Bonaventure Expressway.

However, after several calls to stop the planned clearance of a sewer line, Montreal's executive committee says it will delay the plan for at least several days while it examines the potential for doing something else.

The city applied to the provincial Environment Ministry for permission to drop untreated sewage and was given approval.

On Wednesday, Environment Minister David Heurtel said the department was "led to believe there was no other option."

City officials say that while the amount of sewage being dumped sounds immense, it is well within the capacity of the river -- pointing out the amount of sewage scheduled to be poured out over a week is equivalent to how much water flows through any given point in the St. Lawrence in half an hour.

Craig Sauvé, councillor for Projet Montreal, said that was unacceptable.

"That's a significant amount. It's domestic, industrial, it's medical waste water potentially … How is it that today there's no contingency plan for such a huge operation?” he asked.

It used to be a common practice for the city to drop sewage into the river, but it stopped being a routine occurrence in the 1980s and was last performed six years ago.

The city says it will not be commenting publicly until it decides what to do next.