Prime Minister Tony Abbott has defended the actions of authorities after it was revealed an anonymous tip-off was made about gunman Man Monis less than 48 hours before the Sydney siege.
The call was reportedly made to the National Security Hotline on the weekend before the Lindt Café siege and urged them to check the gunman's website.
"The advice I have is that the call in question was followed up and that the information that was provided didn't expose any threats of direct violence by the Martin Place murderer,” Mr Abbott said.
"So it was followed up. It really was followed up.”
"But it did not reveal any imminent attack by any individual.”
The call will be scrutinised during the government review of the tragic events in Martin Place early this week, which ended in the deaths of hostages Tori Johnson and Katrina Dawson as well as that of Monis himself.
Questions have already been raised about why Monis was allowed out on bail when facing charges of being an accessory to the murder of his ex-wife, and numerous sexual assault allegations.
Authorities are also scrambling to determine how the gunman could have slipped beneath the radar.
The review will take in Monis' social media accounts, where he wrote messages of support for the actions of extremist Sunni group ISIL and of the obsessive letter-writing campaign he carried out against the families of dead Australian soldiers.
It is set to be completed in January.
"What I want to assure you is the joint Commonwealth State investigation is designed to look at all the circumstances of this terrible brush with terrorism, to make sure as much as it is humanly possible that it doesn't happen again," Abbott said.
"I do want to say that I have nothing but admiration for the work of the NSW police.
"It is tragic that two beautiful innocent people were killed.
"The person responsible for this is the terrorist."
