Revellers who've been staking out positions all day to watch Sydney's world-famous New Year's Eve fireworks can expect a "fabulous and safe" display, the city's lord mayor says.
One million people are expected to watch the fireworks from vantage points around Sydney Harbour while another billion will tune in on television.
Lord Mayor Cloover Moore says the City of Sydney has worked closely with NSW Police to make sure the $7 million show is a success.
"There are extra (security) measures tonight, but there's no particular concern, they're just measures that are being taken because of the sorts of things (terrorism) that have been happening around the world," Ms Moore told reporters.
"We have always had a really fabulous, very safe event, and that's what we're counting on doing again tonight."
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NSW Police will use vehicles to block off roads "where appropriate" in an attempt to ensure no-one can use a truck to attack partygoers.
There'll also be concrete and water-filled bollards strategically located across the city.
A high-visibility police operation swept Circular Quay on Sunday morning with officers using mirrors to look for threats.
Almost 45 per cent of those watching around the harbour are international tourists. Guides are written in Chinese, Korean, Japanese, Spanish and German.
"No city, including Melbourne, can compare with Sydney," Ms Moore said on Sunday.
"No other city has the bridge, the harbour, the Opera House and the climate."
There'll be eight tonnes of fireworks producing 100,000 individual pyrotechnic effects.
For the first time, there'll be a countdown to midnight, with fireworks forming the numerals 10 to one on the Harbour Bridge. The word "Sydney" will then be spread across the arch.
Asked if he was confident of getting the timing spot on, fireworks director Fortunato Foti said: "Well it will either work or it won't."
"But we're pretty confident," he added.
During the display, there'll be a rainbow waterfall off the bridge to celebrate the gay marriage vote and the upcoming 40th anniversary of Mardi Gras
Actor Hugh Jackman has designed a brief section of the fireworks which will appear eight minutes into the midnight display.
Sydney's most popular New Year's Eve vantage points began filling early on Sunday morning.
French siblings Laura Hetuin, 20, and her brother Antoine, 16, snared a prime spot at Campbells Cove with views of the bridge and Opera House by arriving at 7am.
They packed sandwiches, water, suncream, card games and good spirits to get them through the 17-hour wait.
"We are really happy we are here (on the top step)," Laura told AAP.
"We came so early because it's Sunday and people aren't working so we thought maybe it would be even more crowded."
Revellers are being urged to catch public transport with extra trains and buses running all afternoon.
Some inner-city roads closed early on Sunday morning with the majority to be shut down by 7pm. After 11pm all roads north of Goulburn Street in the CBD will be closed.
Most roads remain shut until 4am.
