Indonesian police today said an elusive Malaysian bomb expert involved with al-Qaeda-linked Islamic militants was emerging as the prime suspect in a massive bomb attack on the Australian embassy in Jakarta.

Azahari Husin, a former professor and explosives expert believed to have been involved in earlier Jemaah Islamiah bomb attacks in Bali and on Jakarta's Marriott hotel, could be behind the embassy blast in which up to nine people had died.

About 160 people were believed to be wounded by the attack.

"Our prime target is to arrest him (Azahari)," national police chief General Da'i Bachtiar told reporters.

He said the explosion was caused by a car bomb, similar to earlier devices said to be the Malaysian's work.

Bigger blast

The blast ripped the gates of the embassy off and and leaving a three-metre crater in the ground.

A police vehicle and a taxi nearby were badly damaged, and burned motorcycles were strewn about the scene. At least one had a dead rider beside it.

According to Australia's Department of Foreign Affairs and Trade, all Australian staff at the embassy have been accounted for.

The police said the bomb was bigger than that which struck the JW Marriott Hotel nearby in Jakarta on Aug 5 last year.

President Megawati Sukarnoputri was in neighboring Brunei attending a royal wedding cut short her stay to return to Jakarta after learning about the explosion, officials said.

Azahari and compatriot Noordin Mohammad Top are suspected of making the bombs used in the October 2002 Bali bombings in which 202 people died and in the August 2003 attack on the Marriott in which 12 perished.

Both attacks were blamed on the Jemaah Islamiah regional terror group.

"Dr Azahari has the specific capability. Why do we continue to look at this group? Because it (Thursday's bombing) has a very close resemblance to the Bali and the Marriott bombings," Bachtiar said.

Suicide operation?

Bachtiar said Azahari and Noordin, who escaped a police dragnet last year in the city of Bandung on Java island, were constantly on the move but were "definitely still in Indonesia".

Bachtiar said the car is believed to have blown up in front of the embassy and had not yet entered the embassy compound.

But he said it was not clear whether it was the work of a suicide bomber.

Jakarta military commander Major General Agustadi said he believed the attack was a suicide operation.

"From data on the ground it looks like it was a suicide bombing and it was carried out with a car," he said.