Fireworks lit up the sky over Sydney Harbour as Australia's biggest city ushered in the new decade with a spectacular burst of colour and authorities sought to restrain revellers' drinking.
As many as 1.5 million people crowded the foreshore to welcome in the New Year with a firework display that included 10,000 individual effects, part of the city's five million dollar (4.5 million US) party.
New South Wales Premier Kristina Keneally described the celebrations as the "best show on Earth", adding that as many as one billion people would watch on television.
Some 4,500 kilograms (9,000 pounds) of fireworks were set off from the iconic Sydney Harbour Bridge and four barges on the water, bathing the city in colour and light during the 12-minute show.
Organisers said the display was the most complex ever staged, involving computer microchips and a rare blue colour difficult to achieve.
"They were absolutely amazing, I didn't know which way to look," Heather Morgan from Wales said after a version of the display was mounted for families earlier in the evening.
Officials urged revellers to keep a lid on their drinking as some 2,500 police officers patrolled areas crowded with spectators since early Thursday.
"If you're one of these fools that can't handle their grog and likes to go out and ruin other people's nights, make yourself a New Year's resolution to grow up and behave yourself and start practising that on New Year's Eve," police minister Michael Daley said.
Youth Minister Kate Ellis also warned that too much alcohol could turn the occasion into a "nightmare" for young people.
"If you're over 18, enjoy a drink, but don't ruin the party for everyone with drunken violence and reckless decisions," she said.
Members of Drug Free Ambassadors Australia were Thursday handing out booklets urging people to avoid illegal drugs and alcohol at Circular Quay, a popular vantage point for the display.
"We are urging people to spend New Year's Eve drug-free," spokesman Cyrus Brooks said. "Alcohol is also a drug and a little goes a long way."Reuse content