"Should the aircraft not be found within the current search area, ministers agreed to extend the search by an additional 60,000 square kilometers to bring the search area to 120,000 square kilometers and thereby cover the entire highest probability area identified by expert analysis," they said in a joint statement.
"Ministers recognize the additional search area may take up to a year to complete given the adverse weather conditions in the upcoming winter months."
MH370 vanished from radar screens on March 8, 2014 shortly after taking off from Kuala Lumpur, bound for Beijing. No trace has since been found of the Boeing 777 aircraft, which had 239 passengers and crew on board.
Investigators believe the plane was flown thousands of miles off course before eventually crashing.
