sydney siege
Police storm the Lindt Chocolate Cafe at the end of the siegeJoosep Martinson/Getty Images

Sydney siege gunman Man Haron Monis was released on bail despite being identified as a risk to the community, it has emerged.

Australian Prime Minister Tony Abbott said the government would investigate why Monis had been placed on bail and not put on a terror watch list.

Monis, who was shot dead by police on Monday (15 December), was put on conditional bail in May by Parramatta magistrate Joan Baptie after being charged with more than 40 sexual assaults involving seven alleged victims and as an accessory to the murder of his former wife.

This was despite being an "unacceptable" risk to "victims, individuals or the community", the Sydney Morning Herald reported.

New South Wales attorney General Brad Hazzard told the Herald on Tuesday that stricter bail laws that come into effect in January would have meant it would have been "very unlikely" Monis would have been released on bail.

Abbott also questioned why someone with "such a long and chequered history" was not put on "appropriate watch lists".

"How can someone like that be entirely at large. These are questions that we need to look at carefully," he said.

But then he contradicted his statement by saying the Lindt café siege on Monday, which claimed the lives of café manager Tori Johnson, 34, and Sydney lawyer Katrina Dawson, 38, could not have been preventable.

"The level of control that would be necessary to prevent people from going about their daily life would be very, very high indeed," he added.