Feature: Australia reflects on first anniversary of Sydney Siege

Australia is in mourning on Tuesday as the nation remembers the events that unfolded in Sydney's Martin Place that took the lives of Lindt Cafe manager Tori Johnson and barrister Katrina Dawson.

At approximately 0900 local time on this day one year ago, gunman and self described sheikh Man Haron Monis took 17 staff and customers hostage at the Lindt Cafe in Sydney's Martin place. The incent ended in a bloody gun battle with the police special operations unit 16 hours later.

Barrister Katrina Dawson was killed by a ricochet' from the spray of bullets as police stormed the cafe following Monis'execution of manager Tori Johnson that ended the siege. Monis was killed in the exchange fire with police.

Outside the cafe on Tuesday, New South Wales state Premier Mike Baird reflected on the day terror was brought "right here in the heart of our wonderful city."

"I think all of us thought these sorts of events didn't happen here and as we stand here in Martin Place the tragedy is, it did," Baird told reporters.

In the hours following the siege, a social media movement showing solidarity with Australia's Muslim population grew to de-escalate anti-Muslim sentiment in Australia's largest city by supporting those who might have felt marginalised, vulnerable and concerned about revenge.

Baird praised the outpouring of support following the siege by Sydney-siders and Australians alike, primarily illustrated by the sea of flowers in Sydney's Martin Place that brought hope to a damaged city in the face of great diversity.

"We will not be stared down by those who want to bring evil to this city, those that want to divide us, we stand in hope," Baird said.

"That great hope that came is something I don't think anyone that was here will ever forget - and really that is what we stand on today, both in mourning with those we lost - but (also) the great hope that came and was shown by the city in the face of that adversity."

The sea of flowers, that hope, is the inspiration for a permanent memorial of the siege's victims in a "scattered starburst" of some 400 floral cubes to be inlaid into the granite pavers of Martin Place.

"We have worked closely with the Dawson and Johnson families to choose a design that we believe captures the spirit of the outpouring of support we witnessed from people all over NSW," Baird said.

While the nation reflects, an official investigation into the circumstances that led to the deaths of Johnson, Dawson and Monis is continuing.

It's been revealed Monis was on bail for a string of offences including being accessory to the murder of his ex-wife and 40 counts of sexual and indecent assault against six other women at his spiritual healing practice that were laid two months before the siege.

The inquest has heard Monis harboured deep-seated grievances against the Australian government and had pledged allegiance to the Islamic State terror group the week before in a social media post, which domestic spy agency ASIO had investigated but reportedly dismissed.

ASIO which had dealings with Monis since he first claimed asylum from Iran in 1996 regarded the man as a "serial pest" following numerous "tips" to the spy agency concerning the 2000 Sydney Olympics and the London Bombings, among others.

The state coroner administering the inquest offered his condolences and support to the victims and their families but warned the anniversary would be a difficult day of remembrance for all despite the outpouring of support that followed the siege.

"Unexpected and violent deaths cause severe distress and I know it has been traumatic and stressful for everyone to re-live these events as they are replayed in the media and at the inquest," NSW state coroner Michael Barnes said in a statement.

"One year on, we need to remember these feelings will not have subsided, particularly for those directly impacted by the siege. In some instances, it could be worse."

Preceding a public candle-lit memorial service for the siege victims that will be held on Tuesday evening, Baird and NSW Police Commissioner Andrew Scipione shared a cup of coffee at the Lindt Cafe with siege survivor and cafe worker Joel Herat.

"Having had a chance to talk to Joel inside clearly he's still hurting but he's getting on with life and he's to be commended as a young man who has been through this terrible, terrible event," Scipione said, noting all victims are still suffering.

"I gave then, and the guarantee I give now, is that we as law enforcers will do absolutely everything we can to prevent this type of thing from happening again."

Australia has been on heightened alert for attacks by home-grown radicals since September last year. So far the authorities have arrested numerous terror suspects, 11 in Sydney alone, in connection with domestic terror plots.

Last week Australian counter terrorism authorities arrested a 20-year-old man and a 15-year-old teenager in connection with an alleged plot targeting Australian government buildings, including the Australian Federal Police (AFP) headquarters in Sydney.

The two men, and three others already in jail on related charges, are believed to be associates, though no direct links, of those who radicalised a teenager who executed police accountant Curtis Cheng in early October. Endit