Police say they are generally happy with the behaviour of New Year's Eve revellers in Victoria despite having to respond to hundreds of calls about illegal fireworks.

Officers arrested 18 people across the state overnight for alleged offences including assaults, driving offences and property crime.

Victoria Police Acting Superintendent Chris Hamilton said they also responded to 313 incidents related to fireworks.

"I suspect most of those were related to illegal fireworks or homemade fireworks. And sadly, some of those did go pear-shaped," he told ABC Radio Melbourne.

Acting Superintendent Hamilton said a 31-year-old Mickleham man suffered serious facial injuries and burns and was taken to hospital.

"We're talking about really a kind of life-changing eye injury with that man," he said.

A 43-year-old man in Corio was also taken to hospital with a serious finger injury as a result of fireworks.

Police detain a man in Melbourne's CBD on New Year's Eve. (ABC News)

Ambulance Victoria said the night was one of the busiest NYE periods in recent years, with caseloads between midnight and 2am 150 per cent higher than previous years in Melbourne's CBD, and 300 per cent higher in the Geelong region.

There were more than 80 emergency incidents in Melbourne's CBD, with 62 patients treated and 33 taken to hospital.

Ambulance Victoria chief executive officer Jordan Emery said paramedics responded to a wide range of serious and complex incidents overnight.

"Our paramedics treated a number of high acuity cases, including stabbings, serious assaults and fireworks related injuries, alongside the usual mix of medical emergencies, alcohol related illness, trips and falls," Mr Emery said.

"This was a much busier night than previous years, and our teams worked exceptionally hard under sustained pressure to ensure patients received timely and appropriate care."

A rooftop garden at Treasury Place also caught fire due to planned fireworks at 9:30pm but nobody was hurt and there was no significant property damage.

More than 2,000 police officers were deployed across the state on New Year's Eve. Expanded search powers were in effect in Melbourne's CBD, St Kilda and Geelong as part of Operation OMNI.

More than 2,000 police officers were deployed across Victoria on New Year's Eve. (ABC News)

Police said a number of weapons were seized during searches, including an angle grinder, balaclava, gloves and items suspected to be used for breaking and entering.

The items were found on a 17-year-old boy who was wanted by police on other matters. He was charged and bailed to face a children's court at a later date.

A 15-year-old boy was punched in the face and lost a tooth in Southbank.

And police used stop-sticks on a vehicle that took part in a hoon meet at Williams Landing. They arrested a 15-year-old boy and two men aged 23 and 26.

Victoria Police NYE State Commander Belinda Jones said it was a relatively safe celebration across Victoria.

"Overwhelmingly we saw great behaviour by crowds overnight, with people heeding our advice to celebrate safely and responsibly," she said.

"There was a small number of people who took it too far and chose to do the wrong thing. All reported incidents were resolved quickly, ensuring no disruption to the wider community.

"I want to thank every police officer who assisted across the state to ensure Victorians could enjoy the festivities safely."