Australian Prime Minister Tony Abbott has hinted that the search for missing flight MH370 may be scaled back.
But, speaking to MPs and passengers’ relatives ahead of the anniversary of the disappearance, Mr Abbott said he hoped the plane would be found.
He said that those with loved ones aboard the flight had been through a “harrowing nightmare”.
The Malaysia Airlines plane vanished en route from Kuala Lumpur to Beijing on 8 March 2014 with 239 people on board.
“I do reassure the families of our hope and expectation that the ongoing search will succeed,” Mr Abbott told parliament in Canberra.
“I can’t promise that the search will go on at this intensity forever but we will continue our very best efforts to resolve this mystery and provide some answers,” he said.
Mr Abbott’s remarks echo Deputy Prime Minister Warren Truss, who said earlier this week: “We clearly cannot keep searching forever.”
Australia is leading an international search team in the Indian Ocean, approximately 1,600km (1,000 miles) off its west coast.
Search vessels are focused on a 60,000sq km priority zone.
Mr Abbott said on Thursday that the search was taking place in the “Roaring Forties” – “one of the world’s roughest stretches of ocean”.
The search’s A$120m (US$93m: £61m) budget is being jointly put up by Australia and Malaysia.
Australia, Indonesia and Malaysia announced earlier this week they will trial a new method of tracking long-haul flights in the wake of the disappearance.
The trial system enables planes to be tracked every 15 minutes, an increase on the current 30 to 40 minutes.
Malaysia’s Department of Civil Aviation is due to release an interim report on the plane’s disappearance on Saturday.