The search for a missing Indonesian submarine with 53 people aboard on Thursday focused around an oil slick north of the resort island of Bali with help from Australia, Singapore and other countries, Indonesia’s navy said.

The KRI Nanggala 402 was participating in a training exercise on Wednesday when it missed a scheduled reporting call. The oil slick was spotted near the starting position of its last dive, about 60 miles north of Bali.

Indonesian navy spokesman Julius Widjojono said the search included help from several countries, including Australia and Singapore, which have submarine rescue vessels.

Indonesia Submarine
The Indonesian Navy submarine KRI Nanggala takes part in a drill off Cilegon, Indonesia, in in 2017 (AP)

The Indonesian navy has deployed scores of ships to search the area, including a hydrographic survey ship.

Australian Defence Minister Peter Dutton said he would speak to the Indonesian government.

“Australia will obviously provide whatever assistance is possible and we’ll work with other partners in the region to provide whatever assistance we can,” Mr Dutton told Sydney radio station 2GB.

“We will go to the support of our neighbour in any way we can,” Australian Foreign Minister Marise Payne told Australian Broadcasting Corporation radio.

Indonesia Submarine
The KRI Nanggala during exercised in 2014 (AP)

The submarine was carrying 49 crew members, its commander and three gunners, the Indonesian Defence Ministry said.

The navy said an electrical failure may have occurred during the dive, causing the submarine to lose control and become unable to undertake emergency procedures that would have allowed it to resurface. It said it believes the submarine sank to a depth of 2,000-2,300 feet.

The German-built vessel, which has been in service in Indonesia since 1981, was rehearsing for a missile-firing exercise that was to take place on Thursday.

Indonesia currently has a fleet of five submarines and plans to operate at least eight by 2024.

The country, the world’s largest archipelago nation with more than 17,000 islands, has faced growing challenges to its maritime claims in recent years, including numerous incidents involving Chinese vessels near the Natuna islands.