Investigations are under way after a Boeing 787 Dreamliner caught fire at Boston's Logan Airport.

An electrical fire filled the cabin of a Japan Airlines Boeing 787 with smoke minutes after passengers disembarked following a non-stop flight from Tokyo yesterday.

The Massachusetts Port Authority's fire chief, Bob Donahue, said the fire began in a battery pack for the plane's auxiliary power unit, which runs the jet's electrical systems when it is not getting power from its engines.

Fire crews using infrared equipment found flames in a small compartment in the plane's belly and extinguished it in about 20 minutes, he said.

There was a flare-up later when a battery exploded.

"Something caused this battery pack to overheat, ignite," Mr Donahue said, adding it is too soon to know the cause.

The flight landed normally at about 10.15am.

Its 173 passengers and 11 crew members had already got off the jet when a mechanic spotted light smoke in the cockpit and cabin about 15 minutes later and notified Massport.

The mechanic was the only person on board when the fire broke out.

The 787 is Boeing's newest plane, and the first was delivered in late 2011.