Qantas engineers based at Los Angeles International Airport have accused the airline of engaging in unlawful intimidation tactics after they formalised their attempt to unionise.

The International Association of Machinists and Aerospace Workers, a trade union with members in the US and Canada, issued a notice demanding the airline “cease and desist intimidating Qantas employees by threatening their jobs and interfering with their right to support having a union”. It warned threats to outsource their jobs violates US federal law, according to a letter sighted by The Australian Financial Review.