The union claims risk assessments carried out by Airservices Australia reveal Brisbane, Melbourne, Perth and Adelaide airports were found to be at extreme risk if there was a fire or aircraft incident due to a lack of firefighting resources.
United Firefighters Union of Australia members plan to strike for four hours from 6am on April 15 out of concern for the "dire risk" to air travellers.
The union claimed Airservices kept the "leaked internal documents" hidden from the public, but they were provided to Senate estimates proceedings and made publicly available in October 2023.
An Airservices Australia risk assessment found Sydney Airport ill-equipped to handle an emergency. (Damian Shaw/AAP PHOTOS)
Union secretary Wes Garrett says problems remain to this day as Airservices has failed to act on the risk assessments, which were carried out between 2021 and 2022.
"We don't take this action lightly, but the safety of air travellers will always be our first and most important priority," Mr Garrett told reporters on Tuesday.
"We cannot do our job properly unless we are properly staffed and properly resourced."
The documents show travellers at 13 airports including Brisbane, Melbourne, Perth and Adelaide were at an "extreme risk" due to factors including shortages of trucks, frontline and ground control staff, equipment and procedures.
Travellers at 14 other airports, including Sydney, Canberra and Hobart, were deemed "high risk" with the union saying that while they had more resources there were not enough to guarantee safety.
The strike comes amid a bitter industrial dispute between the union and the government-owned corporation which is responsible for providing aviation support services, including firefighting and air traffic control, at airports across the country.
The union wants changes to the enterprise agreement with Airservices to insert new clauses including minimum staffing requirements, set work hours and rostering and make changes to meet work health and safety regulations.
The union is also demanding a pay rise of 20 per cent which Airservices says would cost the aviation industry and passengers an additional $128 million.
Airservices has offered firefighters an 11.2 per cent pay rise in response.
The company denied its operations were unsafe and said the risk assessments were undertaken to guide future staffing planning.
"The dispute has nothing to do with staffing levels, which are monitored and regulated by CASA (Civil Aviation Safety Authority) as the aviation safety regulator," a spokesperson for Airservices Australia said.
"Airservices has sufficient (firefighting) personnel to meet our regulatory obligations and is investing $1 billion over the next 10 years in equipment and facilities for our (firefighting) crews."