A lone survey vessel has left an Australian port for perhaps the final time to search for the Malaysian airliner that mysteriously crashed into the southern Indian Ocean two years ago, officials said Tuesday.

The Dutch survey ship Fugro Equator left Fremantle on Monday night to continue the search for Malaysia Airlines Flight 370 alone, Minister for Infrastructure and Transport Darren Chester's office said.

Whether the voyage is the ship's final monthlong deployment from Fremantle before the search was completed after more than two years would depend on the weather, Chester's office said.

Chester thanked China for the services of a Chinese ship that in February joined the search of a 120,000-square-kilometer (46,000-square-mile) area where authorities calculate that the Boeing 777 crashed with 239 people aboard on March 8, 2014. The Chinese ship started making its way back to Shanghai this month.

Fugro Equator is using a highly maneuverable drone known as an autonomous underwater vehicle to get sonar images of difficult terrain that could not be reliably searched with towed sonar equipment.

The deep sea search has failed to find any trace of the airliner that flew far off course during a flight from Kuala Lumpur to Beijing. But debris confirmed or suspected to be from Flight 370 has washed ashore on the western Indian Ocean at Reunion Island, Mozambique, Tanzania, Madagascar and Mauritius.

Australia is overseeing the search on Malaysia's behalf. The two governments agreed with China in July that if the aircraft was not located in the current search zone, the search would be suspended in the absence of credible new evidence leading to the identification of a specific location.

Passengers' relatives hope that drift analysis of the washed-up debris will provide the new evidence to continue the search.