"We sincerely hope that we will be able to again offer our services in the search for MH370 in the future," Plunkett said.
Malaysia signed a "no cure, no fee" deal with Ocean Infinity in January to resume the hunt for the plane, a year after the official search in the southern Indian Ocean by Australia, Malaysia and China was called off. Ocean Infinity stood to be paid US$70 million ($101.3m) if it had found the wreckage or black boxes. No other search is scheduled.
Australian Transport Minister Michael McCormack said the four-year search had been the largest in aviation history and tested the limits of technology and the capacity of experts and people at sea.
"We will always remain hopeful that one day the aircraft will be located," McCormack's office said in a statement.
Australia, Malaysia and China agreed in 2016 that an official search would only resume if the three countries had credible evidence that identified a specific location for the wreckage. Flight 370 vanished on March 8, 2014, while flying from Kuala Lumpur, Malaysia, to Beijing.
- AP