Stephen Coates, Jakarta – The new chief of Indonesia's antiterror agency has complained that courts were being too easy on terrorists and called for tougher laws to fight jihadist extremists.

National Anti-Terror Agency (BNPT) chief Ansyaad Mbai said there was an "urgent need" to amend antiterror laws following a series of attacks since 2000.

He said sentences should be lengthened, preparatory activities such as militant training and incitement should be criminalized, and police should be able to hold suspects for longer before they must be charged or released.

"I think there's an urgent need to amend the anti-terror laws, especially on the length of sentences," he told reporters after being appointed to his new role.

"There were many who were released [from jail] and then got involved again. There were those who were sentenced to seven years but after three years they were given remissions. This is strange, isn't it?"

He said some terrorists had been arrested but had to be released because police did not have enough time to gather evidence.

"Later it's clear they were involved again and then they had to be shot, like Air Setiawan," he said, referring to an alleged terrorist who was killed by police last year after twin suicide attacks on Jakarta hotels in July.

A follower of terrorist mastermind Noordin Mohammed Top, he was reportedly detained over his suspected role in the 2004 bombing of the Australian embassy in Jakarta but was released due to a lack of evidence.

Police killed Top in September 2009 in one of many raids since the hotel bombings that have resulted in the deaths of suspects, raising questions about alleged extrajudicial killings by the anti-terror police squad.

The discovery of a militant training camp in Aceh province in February – which gathered Islamist extremists from around the region – also highlighted the need for laws against preparatory acts, Mbai said.

"Militant training hasn't been included as a crime... In other countries it's considered a serious crime," he said.

"Then there are those activities which provoke or incite people to carry out acts of terror... The focus is prevention. We have to prevent them before they take part in militant training which means they must be arrested."

He said incitement to burn Christian churches or expel "infidels" should be criminalized to prevent Indonesia being "showered in bombs."

"If there's no conviction we'll always be reactive. Wait for the bomb to go off and only then become nervous. That's too late," he said.

Indonesia was also studying the experience of Saudi Arabia to improve its deradicalization programme, which has been dismissed as a myth by top anti-terror police officers.

Senior police have recently issued stark warnings that the Southeast Asian country's prisons are at risk of becoming schools of violent jihad rather than institutions of reform.

The final straw appears to have been the re-arrest in June of Abdullah Sunata, 32, on suspicion of plotting attacks on the Danish embassy and a police parade.

He was released from jail last year for good behavior after serving only a fraction of a seven-year sentence for his role in the Australian embassy attack, which killed 10 people.

Other recent examples include bomb-maker Bagus Budi Pranoto. Also jailed over the embassy truck bombing, he was released after just four years only to be re-arrested over last year's suicide attacks on luxury hotels which killed seven people.