Several concrete barricades have been erected in Sydney's Martin Place, just outside the Lindt Cafe, as part of ongoing security reviews and work to defend public spaces from any threats.

A City of Sydney spokesperson told the ABC more barricades or bollards will be rolled out to other stages in Martin Place over the coming weeks.

The installation of the barricades was on the advice of NSW Police and state emergency services to block vehicle access.



The barricades are temporary while more permanent measures are considered such as bollards, garden beds or other landscaping features, the spokesperson said.

Martin Place was considered a priority for strengthened security due to the foot traffic it receives being the "civic heart" of Sydney.

The barricades have been erected to strengthen security levels in Martin Place. ( Supplied: Nicholas Eggleston )

Other public places of mass gathering in Sydney were also being reviewed to determine if they too need bollards or barricades, the City of Sydney said.

NSW Police said there was no specific threat to Martin Place but the security measure were a result of studies into vehicle mitigation.

"Ultimately the advice from police involves balancing the management of risk against the need for the public to enjoy access to public spaces," NSW Police said.

Lauren Smith said any measure taken to protect people should be applauded. ( ABC News: Kathleen Calderwood )

Lauren Smith, who is from London where several vehicle-related terror attacks have occurred, was pleased to see the barricades.

"I think it's a bit safer for people, I understand the meaning behind it...with everything going on in the world, it's quite scary.

"If it's there to protect people, it should be there."

On Thursday night, 140 concrete bollards were erected around Melbourne's CBD to reduce the risk of terrorist acts in eight key pedestrian locations.

Six people were killed and dozens injured when a car was deliberately driven through Melbourne's pedestrian-only Bourke Street Mall in January.

Attacks where vehicles are used as weapons have been seen all around the world, including in London earlier this week where a van was driven into a crowd near a mosque.

In June, a van also ploughed into pedestrians on London Bridge, and last year a truck struck hundreds of people in Nice, followed by another truck attack at a market in Berlin.