Two Australian warships will join the search for a missing Indonesian submarine that disappeared near Bali with 53 people on board.

HMAS Ballarat and HMAS Sirius have both been diverted from separate regional deployments, after Indonesia formally accepted Australia’s offer to assist with the search effort.

Defence said HMAS Ballarat was equipped with sonar capabilities and a MH-60R helicopter, and was expected to reach the search area today.

HMAS Sirius is off the coast of Brunei and is expected to reach the search area from about Tuesday.

“Sirius can replenish ships with fuel, water and stores by day and night,” Defence said.

Yesterday, Foreign Minister Marise Payne said Australia would provide whatever support it could to Indonesia.

“We’ve indicated that we will help in any way we can,” she said.

“We operate very different submarines from this one, but the Australian Defence Force and Australian Defence organisation will work with defence operations in Indonesia to determine what we may be able to do.”

Defence said it remained in close contact with Indonesia in case it could provide further help to the search.

Indonesian authorities announced today that rescue teams detected an object with “high magnetic force” floating in seas north of Bali, which they hoped could be the missing sub.

The submarine has been missing for just over 48 hours and was carrying enough oxygen to last three days.

The vessel was carrying 49 crew members, a commander and three gunners.

–ABC