Will Carols still go ahead?

PM Tony Abbott says innocent lives were taken in the Sydney siege because of one man's 'sick fantasies'.

SECURITY at Australia's largest, free Christmas family event filled with celebrity performers is under review in the wake of the Martin Place siege.

Organisers of the Woolworths Carols in the Domain taking place this Saturday in Sydney have responded to concerned fans today, who have been asking if the siege will affect the annual event.

They confirmed on their Facebook page that it is still going ahead, and that they have been in close contact with the NSW Government and Police since yesterday.

They have also had further discussions today, including direct discussions with the NSW Premier's Office.

activeTV, the production company behind Carols in the Domain, issued a statement saying they will continue to deal with the Government and police to protect those attending on the night.

The event, which is broadcast across Australia and attracts more than 50,000 people in the Domain, has a celebrity cast this year including Samantha Jade, Dami Im, Taylor Henderson, Lee Kernaghan, The Wiggles, and Marlisa among others.

NATALIE BARR: Breaks down after Sydney siege on TV

THE GUNMAN: Who is Man Haron Monis?

WORLD ON ALERT: Siege sparks security upgrades overseas

Samantha Jade ... is part of the Carols in the Domain cast. Picture: Adam Taylor Source: News Corp Australia

The Wiggles ... will also appear in the national event before Christmas. Source: Supplied

The event is also being hosted by the entire Sunrise team including David Koch, Samantha Armytage, Natalie Barr and Mark Beretta.

Fans of the event have been posting messages on the event's Facebook page, asking if the event would still be going ahead.

The Sunrise team ... ready to host Woolworths Carols in the Domain. Picture: Supplied Source: Supplied

activeTV's Executive Producer, Michael McKay said: "We take matters of security most seriously and intend to continue to work hand in hand with the NSW Government and Police to ensure all appropriate measures are in place.

"Carols in the Domain plays an important role in our community, even in the best of times, but this year I suspect this role will be more important than ever as a nation comes to grips with the events of the last few days."

Security across Sydney is also being upgraded, as more police hit city streets and businesses hire more private guards.

NSW Police confirmed they have activated Operation Hammerhead for the next three weeks, 24 hours a day.

"The high visibility operation will see extra police deployed across Sydney including transport hubs and networks," a spokesperson said.

Securing streets ... the siege has led to increased police numbers across Sydney. Picture: Bill Hearne Source: News Corp Australia

While an existing operation is in place for Sydney's New Year's Eve celebrations, the spokesperson did not say if changes will be made to it.

"Further details regarding that specific policing operation will be released in the coming days/weeks," she said.

Central Metropolitan Commander, Assistant Commissioner Mick Fuller said Operation Hammerhead will focus on metropolitan Sydney and primarily involve general duties police.

"If need be, those officers will be used wherever our operational intelligence dictates," he said.

"Operation Hammerhead will also patrol iconic locations such as the Harbour and its surrounding foreshores as well as sporting fixtures and other large scale public events.

Meanwhile, Sydney businesses have also stepped up their security since the siege occurred.

Wilson Security has told News Corp Australia that some of its current clients in the last 24 hours have requested more security guards to undertake patrols.

"Our client base is constantly evaluating their security needs, what the risk is perceived to be, and that includes events that have occurred," a Wilson Security spokesman said.

"We've had a number of clients who've increased their security requests in the last 24 hours

for guards and patrols."

Security firm Guardcorp also confirmed there were additional requests for their security guards "in and around the Sydney CBD".

"Our specialty is security guards and patrols, they parol inside and around buildings and have been called in to work at the entry way of buildings, checking identifications," a spokeswoman said.

Harrowing scenes ... the siege ended in casualties and gunfire at the Lindt Cafe at Martin Place, Sydney. Picture: Bill Hearne Source: News Corp Australia

The security workers' union, United Voice, told News Corp Australia that the Martin Place siege was a reminder that we need "good, hardworking people doing their jobs properly".

National Secretary David O'Byrne said that the union's members regularly find themselves in difficult situations, and stressed that working conditions must be right as lives can depend on it.

"The security industry is a difficult industry to work in: the hours are unsociable, the work is difficult and dangerous, but it has low status and the pay is low. It's not surprising that there is high staff turnover," he said.

Reports of increased security locally come as New York police have also ramped up security at landmarks including the Empire State Building, Wall St, Columbus Circle and Times Square, as well as the Australian consulate, in a response to the siege.

Beefing up security ... the New York Police Department have acted after the Sydney siege. Source: AFP

The NYPD is taking no chances following the deadly incident that ended in bloodshed in Sydney early on Tuesday morning.

The city's Hercules Teams, who are the NYPD's elite, special forces-type police units, have been sent to guard the Australian consulate in Manhattan.

"There was a lot of intelligence-driven, strategically-based, high-profile police coverage including the heavily-armed Hercules teams at a number of locations including the consul-general's office for Australia and other Commonwealth countries," NYPD deputy commissioner John Miller said.

Officers from the NYPD's intelligence bureau located in Singapore are also being dispatched to Sydney to work with the AFP and NSW Police to learn more about the siege incident.

Prime Minister Tony Abbott has hosed down suggestions of a copycat attack, saying authorities needed to look calmly and methodically at what occurred and learn the right lessons.

He said the national security committee of cabinet was seeking answers to questions on the minds of all Australians, as the tragedy echoed around the world.

Paying respects ... Australian Prime Minister Tony Abbott and his wife Margaret prepare to lay wreaths at a makeshift memorial. Picture: AFP Source: AFP

"How can someone who has had such a long and chequered history not be on the appropriate watch lists and how can someone like that be entirely at large in the community?" Mr Abbott said.

NSW Premier Mike Baird echoed Mr Abbott's view.

"We are all outraged that this guy was on the street," Mr Baird said.

"We need to ensure that everything is done to learn from this."

Australian Federal Police Commissioner Andrew Colvin said authorities had long warned about the threat of a lone wolf operator.

Investigations would establish the facts and help authorities answer the public's questions, he said.

Self-proclaimed cleric Man Haron Monis and two of his hostages, Tori Johnson and Katrina Dawson, died at the end of the 16-hour siege in the Lindt cafe before dawn on Tuesday.

Five other people — four hostages and a New South Wales police officer — were injured in the incident.