A 16-year-old boy arrested over an alleged Anzac Day terror plot in Sydney is accused of attempting to buy a gun at the weekend.

Counter terrorism police arrested the teenager in his home in Auburn, in Sydney’s west, yesterday afternoon.

He was due to face Parramatta Children’s Court today but his matter was adjourned until tomorrow. It’s expected he will make a bail application.

Court documents state he faces the charge of “do act in preparation and planning for a terrorist act” and police allege that between 12:01am on April 23 and 6pm on April 24 at Auburn the teen “did an act, to wit, attempt to obtain a firearm in preparation and planning for a terrorist act”.

Police are expected to oppose any bail application.

Earlier on Monday, NSW Police Commissioner Andrew Scipione said the age of the suspect was concerning.

“Now, the age of the individual is of significant concern. Sixteen years of age. A boy,” NSW Police Commissioner Andrew Scipione told reporters this morning.

Mr Scipione said the boy had been charged with one count of acts in preparation or planning a terrorist act. The offence carries a maximum penalty of life in jail.

“Police will be alleging it was linked to the Anzac commemorations today,” he said.

The arrest was the result of an investigation by Operation Vianden officers. Police believe the boy was acting alone and the threat had been “thwarted”.

It appeared he had been radicalised online, Mr Scipione said. He was known to security services.

Officers had been monitoring the boy’s online activities and were forced to act yesterday. The 16-year-old was arrested alone on a street near his Auburn home.

“We had to do that to ensure the safety of the community. Clearly we have taken that action with community safety on the eve of the sacred day, which is Anzac Day. I want to assure the community here in NSW that our counter-terrorism capability is such that we are able to move very quickly to prevent harm and on this occasion we have done that,” Mr Scipione said.

“But the threat that was being dealt with was one that caused us to move and to move yesterday. At this stage, this particular young person has been bail refused.”

The teenager’s home was searched but Mr Scipione refused to say what was found, or what sort of attack was planned.

More details would likely emerge later today, including what Anzac Day event was targeted.

Asked if it would have been a devastating attack, he said it was difficult to know. “You don’t know what you don’t know, but what we do know is there was intent clearly where we were satisfied we needed to move and we needed to move swiftly.”

Australian Federal Police Sydney commander Chris Sheehan urged people to attend Anzac Day events today.

“I want to assure the NSW community that our counter terrorism capability is such that we were able to move quickly to prevent harm,” he said.

“Anzac Day should be observed by all in our community free from fear and I would encourage everyone to enjoy this special day.”

Despite that police weren’t leaving “anything to chance” and security at Anzac events today had been upgraded and would be noticeable.

Justice Minister Michael Keenan said the prospect of a terror attack on Anzac Day was a “chilling and disturbing scenario” and a “sad reflection” of the current terror threat Australia faced.

“Those who wish to do us harm — some located here and some overseas — continue to view Australia as a legitimate target,” he said.

‘A STRIKING ATMOSPHERE’

The arrest did not deter Sydneysiders from marking the special day. Thousands attended dawn services from Palm Beach to Penrith.

At the Cenotaph at Martin Place, a third generation veteran and former Royal Australian Air Force pilot officer Gary McFarlane told The Daily Telegraph there was “a striking atmosphere”.

“My father fought in WWII and my grandfather in WWI so today is very much a family tradition.”

When the Last Post was heard many in the large crowd could be seen wiping away tears

Premier Mike Baird joined a host of dignitaries including federal deputy Opposition Leader Tanya Plibersek and Sydney Mayor Clover Moore in laying wreathes.

Across the country, crowd numbers were down compared to 2015, which was marked by massive turnouts to commemorate the 100th anniversary of the Anzac landings.

About 55,000 gathered in the chill Canberra pre-dawn at the Australian War Memorial for the national service, well down on last year’s 120,000-strong crowd.

Memorial director Brendan Nelson said Anzac Day was not about war, but about love and friendship and honouring the men and women who devote their lives to their fellow Australians.

He said it was tempting to settle for the broad brushstrokes, headlines and shallow imagery of our history.

Our comfortable lives bred easy indifference to the individual sacrifice made in our names, he said.

“102,700 Australians are named on the roll of honour. Like us each had only one life, one life to serve others and our nation. They chose us,” he said.

In Brisbane, Governor Paul de Jersey urged a 25,000-strong crowd to show sensitivity to modern-day soldiers carrying the psychological scars of service.

“We must not forget veterans whose war wounds are not readily visible,” he said.

A youth vigil, involving representatives from about a dozen groups including the Scouts, SA Surf Lifesaving and St John Ambulance, was a highlight of Adelaide’s dawn service at the city’s war memorial.

Thousands also gathered at Melbourne’s Shrine of Remembrance and the Auckland War Memorial to pay their respects.

Prime Minister Malcolm Turnbull attended a dawn service at North Bondi RSL club in Sydney and is heading to Canberra for the national Anzac Day ceremony.

Thousands of Tasmanians braved the cold to take part in Anzac Day dawn services around the state. The biggest crowds were at the Cenotaph in Hobart and at Kingston Beach, south of the city, as well as the Cenotaph in Launceston.

RSL Tasmania President Robert Dick said he was glad to see Anzac services so well attended.

“It goes to show how people are remembering those who served our country,” he said.

“It’s fantastic to see.” More than 90 towns in Tasmania are marking the 101st anniversary of the Gallipoli landing with dawn or midmorning services.

Overseas, rain greeted Australians and New Zealanders as they trooped in to the Anzac commemoration site to camp out overnight for the service on Turkey’s Gallipoli Peninsula.

Governor-General Peter Cosgrove will attend the service at Villers-Bretonneux in France.

— additional reporting: AAP

andrew.koubaridis@news.com.au