Montreal’s labour relations board ordered the city’s firefighters' union and its leaders to “take all necessary measures” to ensure fires are responded to without delay.

The ruling comes after nearly three days of mediation between city officials and the firefighters' union.

The two sides went into mediation after the City of Montreal filed a complaint, saying firefighters are deliberately slowing down response times as a way to protest the provincial government's proposed pension reform legislation, Bill 3.

The city official in charge of Montreal’s fire services, Jean Barthelot, told the hearing on Saturday that response times had slowed by 30 to 40 seconds in July and August compared to the same months in 2013.

In the previous four years, response times had varied by only a few seconds, leading Barthelot to suggest they were being deliberately - and dangerously - slowed at the behest of union leaders.

Ronald Martin, head of the firefighters’ union, told the hearings that the allegation was false.

“There is no order from the union to slow responses. Firefighters have always upheld their professionalism. They are dedicated to their work, even if their morale is presently low,” he said at the hearings on Saturday.

On Sunday, the board ordered the union to immediately and publicly state its intention to respect its ruling and inform its members.