Australia's maritime safety watchdog is investigating after a man was seriously injured in a marine accident off Western Australia's north coast.

The 30 year old Bangladeshi man was helping to load iron ore onto a foreign boat at Cockatoo Island on Sunday when a winch handle came free and struck him.

He was flown to Perth with a broken arm, muscle damage, lacerations and burns.

The Australian Maritime Safety Authority's Mr Jonathan Wills said that investigators are keen to speak to the ship's master and crew.

He said “We're still waiting for an incident report to be filed between our vessel surveyors and the ship's master and agent.”

(Sourced from abc.net.au)