Australia's airport firefighters could strike during the Easter long weekend, heavily affecting nationwide travel plans.
The United Firefighters Union of Australia will this afternoon reveal the voting results of a ballot among members on whether to strike.
The union said if firefighters approved the strike, work stoppages could begin as soon as Thursday, March 28 - the day before Good Friday.
The union has accused Airservices Australia of refusing to act over "short staffing and fatigue".
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Potential industrial actions the union flagged include three-hour periods of unavailability for emergencies, full work stoppages of four hours to full shifts, and bans on working overtime.
The union said if the strikes were approved, airlines would be notified "well in advance" so they could reorganise flight schedules.
Nonetheless, it is likely that any strike action would affect travel plans during the school holiday period.
"To cover staff shortages, current aviation firefighters are working unsustainable amounts of overtime to fill the gaps, resulting in massive fatigue. This is unsafe for firefighters and the air travellers they seek to protect," union aviation branch secretary Wes Garrett said.
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"The consequences of aviation firefighters being understaffed at Australia's major airports are potentially catastrophic and could cost hundreds of lives if an air crash were to occur."
Garrett said airlines would be given seven days' notice of any industrial action.
"To address this significant safety problem, aviation firefighters are seeking to add minimum staffing clauses to their employment agreement that would guarantee sufficient numbers of firefighters and trucks on duty to protect air travellers as per international aviation safety law," he said.
