Authorities 'followed protocols on Monis'

An official report into the deadly Sydney siege has reportedly found that authorities followed protocols in their dealings with gunman Man Haron Monis prior to the hostage crisis.

The report, to be released on Sunday, finds there was no system failure in the way immigration, welfare, security and legal authorities acted in relation to Monis, according to The Weekend West newspaper.

But the newspaper says the joint federal-NSW inquiry report is likely to cause cultural change in some government departments, with a tougher stance taken on immigration requirements.

Earlier this month, Prime Minister Tony Abbott said the report was commissioned because "plainly the Martin Place murderer took advantage of our system".

"That's what this report is designed to expose to us and we will take the strongest possible action to ensure this can't happen again," Mr Abbott said at the time.

Hostages Katrina Dawson and Tori Johnson died when the 17-hour siege came to an end at the Lindt cafe in central Sydney on December 16.

Monis, who had taken 18 people hostage, was shot dead when police stormed the cafe, ending the crisis that shocked Australia and made headlines worldwide.

Questions remain about why Monis was out on bail at the time of the siege despite facing 40 sexual and indecent assault charges and why he was granted political asylum after fleeing Iran in 1996.