Tony Abbott admits there were 18 warning calls before Sydney attack

Tony Abbott spoke as the government released the first report into the siege

Tony Abbott says he is chastened by the experience (AFP)

A national security hotline received 18 calls about “self-styled” cleric Man Haron Monis just days before he took 18 people hostage at a café in Sydney, a report into the siege has revealed.

The calls between 9 and 12 December last year all concerned material on his Facebook page.

Just three days later he was shot dead by police after a 17-hour siege which left two hostages dead along with Monis himself.

It was later revealed that the Iranian-born attacker, who had long been known to security services, was out on bail at the time of the attack.

He had been charged with conspiring to murder his ex-wife along with dozens of sexual assaults. In 2012, he was convicted of sending hate mail to the families of Australian soldiers killed in Afghanistan.

The report said all 18 calls were investigated by intelligence and police authorities, but none indicated a specific intention to carry out an attack, meaning that the risk assessment for Monis was not changed.

It further said that “On the basis of the information available at the time, he fell well outside the threshold to be included in the 400 highest priority counter-terrorism investigations."

Prime Minister Tony Abbott, speaking to reporters as the government’s first official review into the attack was released, admitted that “the system has let us down.”

“We don’t believe that at any particular decision-making point, grievous errors were made, but the totality of decision-making let this monster loose in our community.”

He said that Australia would have to reconsider where the line between individual freedoms and the safety of the community would have to be “redrawn”.

“Plainly, this monster should not have been in our community. He shouldn’t have been allowed in the country. He shouldn’t have been out on bail. He shouldn’t have been with a gun. And he shouldn’t have become radicalised.”

Mr Abbott’s comments came as he released a 90 page report conducted by officials from the federal government and the government of New South Wales.