CANBERRA - Surveying vessel Fugro Equator has returned to the Southern Indian Ocean to continue its search for wreckage from missing Malaysian Airlines flight MH370.

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Delays in the arrival of equipment to assist the surveyor had kept the Fugro Equator in dock at Fremantle since Oct 31.

However, it left port on Sunday and has now returned to continue bathymetric operations that it has been conducting since mid-June.

More than 3,000 square kilometers of the ocean floor has been searched since the plane, carrying 227 passengers and 12 crew members went missing in March.

The Fugro Equator will rejoin two other dedicated search vessels, GO Phoenix and Fugro Discovery, in helping to scour a further 160,000 square kilometers of the Southern Indian Ocean.

It is hoped that the three surveyors will now remain at sea for an extended period, with fewer weather warnings expected ahead of the Australian summer.

The three vessels are hoping to locate any significant wreckage, which may include flight recorders, which could assist the Malaysian investigation in providing a detailed map of the possible debris field.