THE search for MH370 will return to more than 30 sites in coming weeks to ensure nothing has been missed.

The latest update on the underwater search reveals the decision to revisit “Classification 2” sites where search vessels have previously made “sonar contacts of interest”.

Despite being rated as “unlikely to be significant to the search” the Australian Transport Safety Bureau now believes they warrant a second look.

media_camera Tough work ... Waves crash over the back deck of Fugro Discovery during search for MH370 in the southern Indian Ocean. Pic: Supplied.

“The resurvey of Classification 2 contacts will be conducted using the deep-tow at lower altitude and using higher frequency sonar,” said the ATSB update.

“The higher resolution data from this method will enable the search team to identify the relevance of such contacts without the need to await the arrival of the autonomous underwater vehicle which cannot be deployed until the weather improves in the summer months.

“The search for MH370 is being conducted thoroughly and to a very high standard and it is important that contacts are comprehensively investigated and considered.”

media_camera Found ... objects thought to be shipping containers on the floor of the southern Indian Ocean.

The decision follows criticism from various experts worldwide about the methods being used to search for the Malaysia Airlines’ Boeing 777 that vanished over 18-months ago.

Former French naval officer Paul-Henry Nargeolet who coordinated the search and recovery of Air France Flight 447, spoke out in May about the “inappropriate equipment” being used, and the inexperience of contractor Fugro to perform the work.

Mr Nargeolet questioned the withdrawal of GO Phoenix, which he said was best equipped for a deep sea search.

Australian and Malaysian authorities have indicated more vessels may join the search when the weather improves.

media_camera Searching ... Fugro Discovery heading out to the search zone in the southern Indian Ocean yet again. Pic: Supplied.

Currently only two, Fugro Discovery and Fugro Equator, are involved in the massive operation over 120,000 square kilometres in the southern Indian Ocean.

A little over half the area has now been scoured, and Australia, Malaysia and China have decreed the search

will not be extended beyond that zone unless new evidence comes to light.

The discovery of a flaperon from MH370 on Reunion Island in July failed to provide any new leads for search co-ordinators.

Australia has funded the lion’s share of the search, contributing $90 million compared with $40 million from Malaysia and nothing from China.

Of the 239 people on board MH370, six were from Australia and 152 from China.

Originally published as Strange new twist in MH370 search