The 7,850 car capacity Hoegh St. Petersburg (built 2009) is combing waters where satellite images suggest there may be wreckage.
The car carrier on a voyage from Europe via Africa to Australia was the nearest vessel to the location so was asked by the Australian search and rescue authorities to become involved.
Sturla Henriksen, chief executive of the Norwegian Shipowners' Association, says the car carrier is the only ship in the area searching for the wreckage.
In a joint press conference with the owner, which was broadcast live on the BBC, Henriksen explained the high freeboard of the vessel made it well suited for search and rescue activities.
Australian navy vessels are en route but will take some time to arrive, Hoegh Autoliners chief executive Ingar Skiaker said during a televised briefing.
A crew of 19 Filipinos are on board the Hoegh St. Petersburg, which Skiaker notes includes a master with 27 years of experience.
The Chinese icebreaker Snow Dragon, which aided the rescue of scientists stranded onboard the 1,764-gt Akademik Shokalskiy (built 1982) off Antarctica over Christmas, is set to leave Perth to join the search.
Satellite images show semi-submerged objects of up to 24 metres long in the water.
Malaysian transport minister, Hishammuddin Hussein, described the possible sighting as a "credible lead".
The Hoegh St. Petersburg has joined aircraft from Australia, New Zealand and the US searching a huge area some 2,500km off Western Australia.
The mystery disappearance of Malaysia Airlines flight MH370 on a flight Kuala Lumpur to Beijing nearly two weeks ago has sparked one of the biggest air and sea searches.
A total of 239 people were aboard the aircraft when transponders reporting its location were turned off and the flight diverted from the course it was scheduled to take.
