New Year's Eve revellers have largely been praised for their behaviour at the nation's largest fireworks shows, while officers were kept busy with outbursts of trouble around local fireworks.
More than a million people swarmed the main vantage points around Sydney Harbour for the city's biggest-ever new year extravaganza as millions of dollars of fireworks went up in smoke.
Skies exploded with colour across Australia and revelry continued into the early hours, with hundreds of thousands of Melbourne partygoers treated to a fireworks and laser spectacular.
Emergency services were kept busy with fireworks-related incidents sparking blazes in Melbourne. (Diego Fedele/AAP PHOTOS)
Police in the nation's two largest cities noted the vast majority of partygoers enjoyed the night safely, although officers were kept busy with violence away from the main celebration areas.
The hunt is on for an attacker wanted over the stabbing of a 17-year-old boy at a park in Guilford in Sydney's west, with police revealing they were called to an incident as a group of males allegedly let off fireworks at a park around 10.40pm.
They boy was taken to hospital in serious but stable condition, with the force now searching for an offender who allegedly fled the scene.
There were some 36 arrests in the Sydney CBD and harbour foreshore areas for offences including assault, affray, robbery and knife possession.
NSW Assistant Commissioner Peter McKenna said the vast majority people enjoyed their night safely and without incident.
"Unfortunately, police were kept busy by a handful of revellers doing the wrong thing, but those people were dealt with quickly," he said.
Police have praised New Year's Eve partygoers, saying most people enjoyed their night safely. (Bianca De Marchi/AAP PHOTOS)
Victoria Police were also pleased with crowd behaviour but disappointed by a significant number of fireworks-related incidents, including three events in Melbourne's north sparking fires on December 31.
"Despite no serious harm caused on this occasion, fireworks carry the risk of serious injury or death, whilst being unpredictable and volatile items that can result in fires," police said in a statement.
There were some 287 reports of fireworks-related incidents across the state, including illegal products seized, as well as more than 50 assaults.
A teenager is in hospital with non-life threatening injuries after he was approached by a group and stabbed at a popular holiday spot on the Mornington Peninsula just before 6pm.
Police said the group fled but two teens were quickly identified and arrested over the Blairgowrie attack, warning police will remain visible across the state on New Year's Day.
Revellers in Queensland and Tasmania were also generally well-behaved, police said.
In his new year message, Prime Minister Anthony Albanese said despite times still being tough the nation could head into 2025 optimistically with wages rising and inflation falling.
Federal Opposition Leader Peter Dutton urged Australians to "reignite our national confidence and our sense of hope" - by electing the Liberal-National coalition in 2025.
Sydney's first baby to be born in 2025 was delivered at 12.32am at the Royal Hospital for Women, with NSW health authorities saying both the mother and baby boy were doing well.
Here's some of what Australians can look forward to, or not, in 2025:
ECONOMY
* The wait for mortgage relief drags on with the Commonwealth Bank and bond markets suggesting the Reserve Bank of Australia may start easing interest rates in February, while the other big four banks tip a May start
* Following some good news that more people have been finding employment, more than a million Australians will get an immediate new year bonus with welfare payments for young people, students, carers and others rising under indexation to keep up with inflation
POLITICS
* With a federal election due by May 17, bookmakers are tipping the coalition to win while the latest polls suggest a knife-edge outcome
* Australia anxiously waits to see if Donald Trump will disrupt the nation's trade with new tariffs and the AUKUS defence arrangement after being sworn in as US president on January 20
WEATHER
* The Bureau of Meteorology forecasts warmer-than-average temperatures across the continent over the next three months and a wetter-than-average season for large parts of eastern, western and southern Australia.