"This morning, the Prime Minister (Najib Razak) received a call from the Prime Minister of Australia (Tony Abbott), informing him that two possible objects related to the search for MH370 had been identified in the southern Indian Ocean," Defence and Transport Minister Hishammuddin Hussein told reporters in Kuala Lumpur.
"We now have a credible lead," he said, adding this "requires us overnight to verify and corroborate it".
Officials said one should not jump to any early conclusion as the hunt for the Boeing 777-200 missing since March 8 had thrown up several false leads.
Australian military-led search aircraft were dispatched to check whether the two objects were the wreckage of the missing Malaysian jet.
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One of the objects spotted by satellite imagery was 24 meters (about 80 ft) in length and the other was 5 meters (15 ft).
"Data markers balls will be dropped" by the planes heading towards the objects, he said.
"There is an urgency to find black box to find answers," he said, but cautioned that these sightings, while credible, are still to be confirmed.
Australian officials said satellite imagery showed the objects were around 2,500 km southwest of Perth, one of the remotest parts of the globe, and appeared to be awash over water several thousand metres deep.