Police are ramping up their anti-terrorism measures for the 40th Annual Sydney Gay and Lesbian Mardi Gras Parade on Saturday.
NSW Police Assistant Commissioner Tony Crandell said Saturday's event will "probably be the largest (one) that we've ever policed" due to the 40th anniversary and the recent passing of same-sex marriage legislation.
Assistant Commissioner Crandell said there will be protective barriers around the area, "strategically placed so we can make sure there's a vehicle mitigation strategy".
He said while there had been no specific terror threat to Mardi Gras, "we understand that the terrorism threat throughout the nation is probable".
More than 1,000 police officers will be involved the operation on Saturday on Sydney's Oxford and Flinders Streets.
"We want to make sure the footprint is secure, that people are safe and enjoy themselves with the comfort of safety," he said.
"There is a terrorism overlay that has been conducted, there are a large number of police officers that are working both in uniform and plain clothes to make sure people are safe."
With record crowds expected, Mr Crandell advised attendees to "ensure you plan your night ahead of time; know how you're getting there, what you're doing at the parade and how you're getting home."
A NSW Police statement said the operation will include an intelligence crew, mounted police, the riot squad and sniffer dogs at the after-party, where music legend Cher will perform.
Mr Crandell also reiterated the force's official apology issued in 2016 for the past behaviour of officers.
"It's important we acknowledge when we get things wrong," Mr Crandell said.
"The NSW Police force got it wrong in 1978. I'm in a position now ... to make certain we don't return to the days of 1978."
Additional reporting: AAP
