The two CH-47 Chinook helicopters touched down at Warrnambool airport with onlookers and staff from the air ambulance stopping to see the massive aircraft.

The helicopters are based in Townsville and it's believed they are undertaking a training exercise at Mount Hotham.

Air Warrnambool chief flying instructor Tony Franc said he heard the helicopters fly over his house and went to have a look.

Mr Franc said the aircraft was impressive to look out.

"It doesn't happen very often," he said.

Chinooks have been involved in defence force operations in Afghanistan since 2006.

The roles of the Chinooks include troop movement, battlefield equipment transport, search and rescue and disaster relief.