The Sydney Harbour Bridge erupted with fireworks to welcome in 2007. (Reuters)
Up to one million people have watched a $3 million fireworks display over Sydney Harbour to welcome in the new year.
The display included a sparkling diamond and a coathanger representing the Sydney Harbour Bridge, which will celebrate its 75th anniversary in 2007.
Earlier in the night, families were treated to a fireworks display with a theme from The Wizard of Oz. The display ended with a massive rainbow effect.
Police say crowds have generally been well behaved, despite 12 arrests being made.
The arrests have been for various offences including robbery, drink driving and affray.
Around the country
Tens of thousands of Queenslanders have welcomed in the new year in the state's hot spots.
Police say a crowd of about 30,000 at Surfer's Paradise on the Gold Coast has been generally well behaved.
Meanwhile, a large crowd watched fireworks on the Brisbane River.
In Melbourne, a male is in police custody after assaulting a transit officer on a train near Laverton West.
Another male has been arrested for an assault on a man at North Melbourne railway station.
Despite this, police say they are pleased with crowd conduct, and most arrests are for alcohol-related offences.
In Tasmania, about 30,000 people have watched a midnight display of fireworks on Hobart Harbour.
The Sydney Harbour Bridge was the centrepiece of the city's New Year celebrations

A crowd of approximately 1 million has welcomed the new year in Sydney overnight. Many of the crowd had camped out since 6 AM AEDT (7PM UTC) to ensure they had the best vantage point for the fireworks displays at 9 PM and 12 AM. Earlier predictions of rain failed to dampen enthusiastic revellers and fortunately did not eventuate.

According to police, vantage points were Circular Quay and Sydney Opera House closed around 7 PM.

This year's theme was "A diamond night in Emerald City" and celebrated the Sydney Harbour Bridge's diamond anniversary of 75 years which will fall in March.

As usual, the bridge became the centre piece of Sydney's celebrations with a question mark turning into a coat hanger during the 9 PM fireworks show before a diamond appeared at 11 PM.

Entertainment was held in the city throughout the day, culminating in a spectacular fireworks display at midnight. Revellers counted down the final seconds of 2006 with numbers on the side of the Sydney Harbour Bridge.

The festivities are estimated to have cost AUD $4 million and organisers claim their fireworks display is "the largest in the world". Sydney's celebrations were broadcast on television live around the world as other countries prepared their New Year's Eve celebrations.

Despite the large crowd, police made only 58 arrests for offences including offensive conduct, stealing, assaulting police, goods in custody, assault, drink driving and affray.

Ambulance officers were called to 1,139 incidents in Sydney with another 900 in country areas.