Qantas plane grounded by gas smell

A smell of gas grounded a passenger jet at Cairns Airport.

An airport spokeswoman said the Qantas flight was boarding when passengers reported smelling gas.

The pilot called emergency services at 4pm and fire and ambulance crews were sent to the scene.

A Queensland Fire and Emergency Services spokeswoman said fire crews cleared all fumes from the site, but had not yet been able to determine the cause of the smell.

Paramedics treated two patients believed to have inhaled the fumes.

A Queensland Ambulance Services spokeswoman said the patients were conscious and unlikely to require hospital transport.

Another flight was also delayed at the airport when a flock of ducks held up a TigerAir flight that had touched down from Melbourne about 11am.