The New South Wales Police Association has vowed to keep its members safe in the wake of the Sydney shooting and urged the public to focus on the victim, Curtis Cheng, rather than the gunman who killed him.

NSW Police Association vice-president Pat Gooley expressed his condolences on Sunday to the family 17-year police force veteran Mr Cheng, who was gunned down at close range outside the police headquarters in Parramatta as he left work at 4:30pm on Friday.

Police have said the 15-year-old gunman Farhad Jabar Khalil Mohammad was politically motivated and had links to terrorism.

Key points: NSW Police Association seeks to increase security at stations

NSW Police Association seeks to increase security at stations Association vows to never mention name of gunman

Association vows to never mention name of gunman Family of victim Curtis Cheng thanks community after loss of "gentle and loving father"

Mr Gooley said police had put in place a terrorism security assessment plan last year, but he had spoken to Police Commissioner Andrew Scipione directly about increasing security at stations since Friday's shooting.

"Our message is we'll keep Police Association members safe and the police commissioner is helping us do that," Mr Gooley said.

He said while police had been injured in terrorism incidents before, this was the first time in the state they were directly targeted.

"What changed on Friday night is that this is the first time in NSW that the NSW Police have been directly targeted as part of a terror incident," Mr Gooley said.

Curtis Cheng's family have thanked the community for their support in the wake of his death. ( Supplied: NSW Police )

He said police had refused to focus on the gunman and give him any further publicity.

"No member of the Police Association will ever mention the young man's name again and I hope that members of the community will do the same," he said.

Mr Gooley also launched a NSW Police Legacy appeal for the family of Mr Cheng, who had worked in the police force's finance department as an accountant for more than a decade.

"Unfortunately the Cheng family has been deprived not only of a loved one but of his financial support," he said.

Mr Cheng's family has released a statement thanking NSW Police and the wider community for their support after the loss of "a kind, gentle and loving father".

"To the many people who have offered their condolences and kind words about [Mr Cheng], we are extremely moved by your thoughts and sympathies," the statement said.

"We are touched by the personal visit from the New South Wales Premier and the police commissioner.

"This was a comforting reminder of the warm regard that was held for him, especially by the New South Wales police community."

What we know about the gunman 15-year-old boy

15-year-old boy Iraqi-Kurdish background

Iraqi-Kurdish background Born in Iran

Born in Iran Actions believed to be politically motivated and linked to terrorism

Actions believed to be politically motivated and linked to terrorism Believed to have been working alone

Believed to have been working alone Has family in Australia

Has family in Australia Resided in the Parramatta area

Resided in the Parramatta area Was not known to police and had no criminal history

The Federal Government has reached out to Muslim community leaders to form a "frontline against teenage terrorism" and urged people not to blame or vilify the rest of the Muslim community.

The Kurdistan regional government representative in Australia also released a statement urging people not to associate the "evil act" with the minority group.

"We wish to emphasise that the evil act carried out by an individual of Kurdish background [shouldn't] be stereotyped to tarnish the reputation of Kurdish community in Australia," the statement said.

"What happened on October 2, 2015, has shocked us and it is absolutely unacceptable. We condemn this vicious act in the strongest possible terms."

Mosque searched for black backpack belonging to shooter

It is believed Farhad attended Parramatta Mosque a few blocks away before changing into black robes and heading to police headquarters on Friday afternoon.

A senior figure at the Parramatta mosque has confirmed that police searched the mosque to look for a black backpack which they believe Farhad used to carry the gun he used to kill Mr Cheng.

Police said the warrant was undertaken by arrangement with leadership at the mosque, who gave their full assistance to police.

Police also searched Farhad's North Parramatta home and confiscated computer equipment.

Map Parramatta Mosque in relation to NSW Police headquarters

A police source said the teenager had been armed with a revolver and did not know Mr Cheng.

Sorry, this video has expired GRAPHIC CONTENT: Video shows shooter outside Parramatta police headquarters

The ABC's police source said the gunman walked past a plain clothes female detective before carrying out the attack.

"She was wearing a business suit and she wasn't carrying a gun," the source said.

"This poor bloke [the victim] was apparently the first one to walk out of the building — he had a connection to the police force — that was it."

The ABC was told by a senior police source that it was the older brother of the Parramatta shooter who tipped off them off about the identity of Farhad.

It is also understood Farhad's sister Shadi went missing on Thursday and flew out of Australia on a Singapore Airlines flight bound for Istanbul, and may be attempting to reach Iraq or Syria.

Her family told police she had taken all her belongings.