The Australian pilots' union is taking legal action in a bid to secure better pay and conditions for New Zealand-based pilots working for a Qantas subsidiary, Jetconnect.

They are paid 40 per cent less than their Australian counterparts.

Jetconnect operates many of Qantas's transtasman flights, but the planes are in Qantas livery and the crews wear Qantas uniforms, so passengers would not know the difference.

The Australian and International Pilots Association says Jetconnect pilots are not paid even the minimum basic wage for a pilot in Australia, and their Qantas colleague make more than that minimum.

The union yesterday took the case to the Fair Work Australia workplace relations tribunal.

Its vice-president Captain Richard Woodward said: "Qantas has chosen to set up a company in New Zealand, paying wages that are below even the modern pilots' award that the Government established recently for pilots."

The union says Jetconnect pilots also miss out on superannuation.

Qantas is fighting the action, claiming Jetconnect pilots are paid fairly.

Its head of government and corporate affairs, David Epstein, told ABC radio: "It's really quite simple. We have New Zealand staff operating New Zealand-originated aircraft, operated by a New Zealand company on aircraft that are registered in New Zealand."

But Mr Woodward said he believed Qantas was deliberately driving down wages by using its cheaper Jetconnect pilots to fly the less profitable transtasman route.

Offshoots of the airline's no-frills subsidiary, Jetstar, were based in Vietnam, Singapore and New Zealand.

"So Qantas is slowly divesting itself into other entities, other small companies, to fly their routes where they think they can make greater profit margins and pay cheaper wages."