The Malaysian government insists it needs more compelling evidence to resume the search for MH370 despite experts maintaining the missing aircraft is probably to the north of where they had been looking.
The Australian Transport Safety Bureau last month reported the Boeing 777 could be within a 25,000 square kilometre area to the north of the 120,000 sq km official underwater search zone in the southern Indian Ocean.
But the search was still called off and the last vessel, the Fugro Equator, returned to Western Australia overnight.
"It's highly likely the area now defined by the experts contains the aircraft but that's not absolutely for certain," Australian Transport Safety Bureau chief commissioner Greg Hood told reporters in Perth on Monday.
Mr Hood said the ATSB would have liked to continue searching to solve the mystery and bring closure to relatives, but the decision to suspend the hunt was made by the Malaysian, Australian and Chinese governments.
"Everybody wants to do the right thing - everybody's got hopes," Mr Hood told AAP.
"Having met a number of family members personally, they continue to have protracted and prolonged grief.
"I'm profoundly sorry for these people."
Australian transport minister Darren Chester said it was understandable relatives and the search team were disappointed to have no answers almost three years on.
His Malaysian counterpart Dato Sri Liow Tiong said the new zone was not enough to go on and it was hoped debris drift modelling would help narrow the plane's location.
While Mr Liow's deputy last week suggested the Malaysian government was open to rewarding private searchers who find the fuselage, the minister said that was a "personal view" and not a government commitment.
While in Perth, Mr Liow met with Aircrash Support Group of Australia chairperson Sheryl Keen, who handed him letters from relatives pleading for the search to resume.
"We need more credible evidence before we move to the next search area," Mr Liow said.
"That area is not specific enough to locate the site of the aircraft."
About 25 pieces of debris have been collected from Africa's east coast and more was expected to wash ashore, he said.
Three pieces have been confirmed as definitely being from MH370, another five are considered "most certainly" from the plane and the rest are still being evaluated.
"We'll continue to work on the debris and work with all the countries concerned," Mr Liow said.
"We're committed to continue with the search for the debris and from then on, we hope we can get more credible evidence for the undersea search.
"We don't want to raise too high a hope to the family members but ... will continue to analyse data."
Mr Hood said drift modelling became less accurate as time went on.
Authorities are also re-examining satellite imagery from around the time of the crash to look for clues.