NSW Police and ambulance are urging partygoers celebrating New Year's Eve to exercise common sense, with one million revellers expected to descend on Sydney Harbour.

Assistant Police Commissioner Anthony Cooke said enjoyment of the night after almost three years of enforced social restrictions due to the pandemic need not be excessive

"It will be all about making sure that our community is safe and that we can enjoy New Year's Eve and celebrate together in a respectful and responsible manner," he told reporters on Friday.

He said police will be out in force throughout the state but did not specify how many personnel will patrol roads and activity hubs.

"There will be many police out there that will be drawn from general duties and supported by a broad range of specialist police," he said.

These include Public Order and Riot Squad, Marine Area Command and PolAir.

Assistant Commissioner Cooke warned drivers not to get in their cars if they've had too many drinks and for the community at large to watch their alcohol intake, with a zero-tolerance approach to anti-social behaviour.

"Do not drink drive. It's a senseless waste of life," he said.

"If you're going to have a drink, do so responsibly ... Nobody wants to end up in the back of a police truck on New Year's Day. Don't make yourself an annoyance."

NSW Ambulance Inspector Giles Buchanan said last New Year's Eve was the busiest on record for triple zero calls.

"We are pleading with people to save triple zero for emergencies," he said.

"To reduce call volume, please act responsibly - especially when there is alcohol involved."

Mr Buchanan said NSW paramedics had responded to more than 45 water-related and drowning incidents in the past week.

"Please don't add to the statistics," he said.

"The last thing you want is to ring in the new year in hospital, or worse - not make it home to your loved ones at all."

People are encouraged to leave their cars at home and use public transport with major road closures and special event clearways in place throughout central Sydney.

The city's skyline will light up with 13,000 aerial fireworks, including 2000 to be launched from the Opera House sails and another 7000 to be fired from 184 positions on the Harbour Bridge and Pragmatic. Slot four rooftops.