CANBERRA - Australian navy vessel Ocean Shield is back in the Indian Ocean to search for missing Malaysia Airlines flight MH370.

After a short port visit, the vessel returned on Tuesday to the vicinity of the acoustic signals picked up by the towed pinger locator in April, Australia's Joint Agency Coordinating Centre (JACC) said in a statement on Wednesday.

The Autonomous Underwater Vehicle, Bluefin-21, was deployed from Ocean Shield on Tuesday afternoon but was recovered about two hours later to investigate communications problems, JACC said, adding that the submarine has not been redeployed.

The international search effort presently includes assets from Australia, China, Malaysia and the United States.

The JACC, which has been coordinating the search operations for MH370, has relocated from Perth to Canberra and is based at the Department of Infrastructure and Regional Development.

It now has a Military Coordination and Sub-Surface Planning Cell, which includes a Royal Australian Navy Hydrographer and US Navy Sea Systems Command representative.

The JACC said a Chinese survey ship is now in the search area and will assist in preparations for future operations. Vessels from Australia, Malaysia and China, as well as an Australia navy aircraft remain on standby should any debris on the surface require investigation.