The Canadian Union of Public Employees, representing more than 10,000 Air Canada cabin crew, on Wednesday gave the airline a 72-hour deadline to reach a pay deal or face a strike, hours after the carrier sought federal government intervention.

The strike is set to begin at about 1am ET, or 1pm Hong Kong time, on Saturday. Around 99.7 percent of employees represented by the union voted for a strike.

The airline, which has warned of potential flight disruptions, declared a deadlock in negotiations on Tuesday, after the union rejected its proposal for binding arbitration.

The carrier had offered a 38 percent increase in total compensation for flight attendants over four years, with a 25 percent raise in the first year.

However, the union said the offer was "below inflation, below market value, below minimum wage – and still leaves flight attendants unpaid for all hours of work".

Most airlines pay cabin crew only for time spent in flight, but flight attendants in North America are seeking pay for all hours worked, including boarding and waiting at airports before and between flights.

The airline had on Wednesday issued a lockout notice to employees, which would start 32 minutes after the strike begins. (Reuters)