Two men have suffered injuries after a bulk carrier caught fire off the Pilbara coast in WA.

A blaze was ignited in the engine room of the Panama-registered South Korea-run cargo ship MV Marigold, which was moored at Finucane Island.

Three crewmembers were treated for burns, one of whom was reportedly in a serious condition.

The Australian Transport Safety Bureau says it will launch and investigation into the incident this week.

Early indications suggest the fire started in the turbo charger for one of three generators that pump out ballast water when the ship is moored.

The engine room was flooded with fire suppressant and the ship is now relying on shore power.

The injured crew are allegedly Burmese and South Korean in origin.

International Transport Workers Federation coordinator Dean Summers told The West Australian that the constantly increasing amounts of material being loaded at resource ports puts overwhelming pressure on workers.

“There always has to be a focus on safety above all else, but particularly in places like Port Hedland, where they're all about exporting iron ore as quickly as they can,” he said.

“There are a lot of ships going back and forth, a lot of ships waiting to come in and there's pressure on everybody.

“The pressure on these workers is enormous and essentially they're an invisible workforce.

“Ships are getting bigger all the time, crews are getting smaller and something's got to give.” he said.