The detention of suspects after last October's Bali nightclub attack stopped them from carrying out another atrocity, Australian police have claimed.

Federal Police Commissioner Mick Keelty said the militant group Jemaah Islamiah, widely blamed for the Bali bombing, had plotted a second attack in Indonesia late last year.

It's clear that they were not only sophisticated but they were very determined in what they were going to do Mick Keelty, Australian Federal Police Commissioner

But he told Australian public radio that police action had prevented a repeat of the Bali atrocity which killed nearly 200 people, around half of them Australian tourists.

Thirty suspects have been arrested in connection with the twin bomb blasts on Kuta Beach, including the reputed mastermind Imam Samudra and Ali Imron, who police say drove one of the vans packed with explosives.

Mr Keelty declined to say where in Indonesia the second attack was to have occurred.

"The attack was a second attack in Indonesia that has been foiled through the arrest of the people responsible, particularly Samudra and Ali Imron," he told the Australian Broadcasting Corporation.

"It's clear that they were not only sophisticated but they were very determined in what they were going to do," he said.

Officials say evidence is growing against Abu Bakar Ba'asyir

"If it wasn't for the work of the Indonesian national police, helped by Australian police, I think we would have probably had another event occur using the skills and the knowledge that Jemaah Islamiah has accumulated over time."

Mr Keelty added that there was growing evidence linking a senior Islamic cleric, Abu Bakar Ba'asyir, to the Bali bombing.

Earlier this week, Indonesian authorities said the alleged spiritual leader of Jemaah Islamiah was likely to be charged in connection with the attack.

But first the cleric will be tried or released on charges linked to a series of church bombings in Indonesia in December 2000 and an alleged assassination plot against Megawati Sukarnoputri before she became Indonesian president.