Malaysia’s transport ministry said Saturday that a new search plan will be implemented if Malaysia Airlines Flight MH370 is not found by the end of May. Liow Tiong Lai’s statement comes a day ahead of the one-year anniversary of the disappearance of the plane, which has triggered the most expensive search operation in aviation history.

Three countries leading the search operations -- Australia, Malaysia and China -- will review satellite data again with the help of experts to devise a new search plan. The countries are due to meet next month to discuss the search operations, according to The Associated Press (AP), and Lai reportedly said that he remains optimistic that the plane will be found in the remote part of the southern Indian Ocean where the search operation is currently underway. 

"By the end of May, if we still can't find the plane, then we will have to go back to the drawing board," Lai said during an interview, according to AP. "We rely on the expert group ... to come up with the plan. I am cautiously optimistic it should be in this area.

"We need directions, we need plans, we need to review all the data that we have," he reportedly said.

Last month, the Malaysian government declared the disappearance of the Boeing 777-200 as an accident and all 239 people on board were presumed dead. However, authorities said that they would continue the search efforts.

Lai also reportedly said that over 40 percent of the 23,166-square-mile priority search area, located about 1,100 miles off the western coast of Australia, has been scoured so far. And according to a report Lai received Friday, 10 hard objects identified by the search team are yet to be analyzed, AP reported.

Earlier this week, Martin Dolan, chief commissioner of the Australian Transport Safety Bureau, which is leading the search, said that a sonar search had found some manmade items such as shipping containers, but there was nothing that resembled debris from Flight MH370.

Meanwhile, former Australian defense chief Sir Angus Houston said Friday that he was hopeful that authorities will soon have a breakthough in the search for the plane, which went missing on March 8 while on its way to Beijing from Kuala Lumpur.

“It’s very important that we continue the search to try and find the aircraft, and hopefully find the aircraft, so that they can reach that closure that they so much desire,” Houston said, according to The Guardian. "I think on the balance of probabilities at the moment, the chances of finding it are still good, and we should be patient and persist with the search."

The search for Air France Flight 447, which went missing with 228 people during a flight from Rio de Janeiro to Paris, in June 2009, lasted for over a year without success before authorities enlisted the help of statisticians to re-examine the evidence, and the plane was found a week later, according to the MIT Technology Review.

“I’m still quietly optimistic that ... one day, hopefully very soon, we might wake up and hear that it’s been found," he added.

Australia's Prime Minister Tony Abbott said Thursday: "I can't promise that the search will go on at this intensity forever," but added, "we will continue our very best efforts to resolve this mystery and provide some answers."