The Indonesian navy today sent dozens of ships to take part in a major naval exercise off the east coast of Borneo near waters disputed with neighbouring Malaysia, a navy spokesman said.

The exercise, codenamed Armada Jaya XXY, will include a beach landing by marines at Sanggata just south of the border with Sabah, as well as manoeuvres in the Sulawesi Sea near an area also claimed by Malaysia, Eastern Fleet spokesman Toni Syaiful told AFP .

"Most of the ships left Surabaya today and the rest will follow tomorrow," Syaiful said, adding that a total of 36 ships would leave Surabaya in East Java, where the eastern fleet is based.

He said the ships carried around 5,000 personnel including marines and a variety of exercises would also be held on the way there.

The ships are to return to Surabaya on December 18.

Warships collided

Syaiful last month described the exercise as Indonesia's largest-ever but denied it was a show of force.

In April warships from Indonesia and Malaysia collided with each other just north of the exercise area but no serious damage resulted.

Tension between the two countries has increased since Malaysia granted permission to Anglo-Dutch oil giant Shell Group to conduct exploration in the area last year.

Since then, the two countries have deployed warships to the disputed area and stepped up their respective patrolling.