MONTREAL -- The Canada Industrial Relations Board (CIRB) on Tuesday ordered striking airport refuellers back to the bargaining table immediately.

Workers in charge of refuelling planes at both Montreal’s Pierre Elliott Trudeau International Airport and Mirabel Airport walked off the job earlier Tuesday.

The walkout comes after workers rejected a deal presented by their union last week by a vote of 90 per cent. Some 99 per cent of members had earlier voted in favour of the strike.

Their employer, Swissport, had filed a complaint earlier this week with the CIRB alleging that the union did not bargain in good faith. On Tuesday, the CIRB upheld Swissport's complaint.

According to the labour board ruling, the tentative deal included a provision that the union would recommend its members vote in favour of it.

The labour board also said the union didn't tell Swissport about the vote result. Instead, the union gave the company a 72-hour strike notice and on Sunday, "made new demands that were estimated to be more than double what was in the tentative contract deal."

In a statement, Swissport welcomed the ruling and said fueling operations were working as normally scheduled.

"Swissport invites the union to respect the ruling and to propose a meeting as soon as possible. Our team has taken over the fueling activities since 11 a.m. today without any delay or incident," the statement said.

The ruling does not affect the strike, which began Tuesday at 11 a.m. when talks between both sides broke off, prompting about 100 employees to walk off the job.

"What we want is an employment contract that respects the workers. It’s disappointing to have to go on strike to make the employer understand that,” said union executive Peter Tsoukalas. “Our attitude has not changed. Our intention is to reach a win-win agreement… We were disappointed to see the employer mobilize its resources to try to invalidate our right to strike.”

All day Tuesday, many flights posted on the website of Montreal-Trudeau had been listed as delayed, but a spokesperson for the airport authority said those problems were due to bad weather.

Trudeau airport officials say they are working with Swissport “to rapidly deploy its contingency plan, including providing managers with access to restricted zones so that they can ensure the continuation of aircraft refuelling activities.”

"We want to reassure the travelling public and our customers that we have the properly trained resources in place to continue refuelling activities," Swissport said. "We are working with airport authorities to minimize any disruptions to travellers.

"So far, it is business as usual and we will be keeping a close watch to ensure that it remains this way. Officials note they are monitoring the situation, but the dispute could result in flight delays."

The contract for unionized workers, including aircraft refuellers, mechanics, dispatchers and maintenance employees, ended last August.

The workers say their main concerns are wages and work-life balance.

The Canadian Press contributed to this story.