Montreal will put 2400 city employees on suspension without pay after they took part in an illegal strike last week.

The employees had warned of the job action, but the city filed to have it stopped, and the provincial essential services council said the job action would not be legal.

Thousands of blue collar workers took part in the union meeting anyway.

Now those employees are facing a week-long suspension, while the union president and three other senior union members are facing two months without pay.

Mayor Denis Coderre said he wants city workers to know this kind of action can never happen again.

"We have to send a clear and strong message that we have zero tolerance with regards to illegal strikes," said Coderre.

City workers have a contract until the end of Dec. 2017, and Coderre said they have to respect their contract.

The union is planning to contest the suspensions.

Projet Montreal leader Luc Ferrandez said he feels the week-long suspensions may be too harsh, given the illegal strike lasted about two hours.

He adds a two day suspension would be appropriate.

"It is an illegal strike and we have to react, that's for sure," said Ferrandez. "But it is maybe the less bad, less important in terms of impact illegal strike we ever had."

"I'm afraid it's just throwing gasoline on the fire."

The city is drawing up a list of all those who attended the meeting, and notes they will not all be suspended at the same time.