Daniel, 17, was waiting for a bus when his face was slashed by a broken bottle in an apparently unprovoked attack.

"I was holding my mouth . . . and I realised I was breathing through my cheek," Daniel told Channel 10.

"It was just a big gaping wound."

His family, including mother Deb, rushed to Perth to be at his bedside.

"If (the wound) was much lower or much higher, it would be a very different story today," Ms Bryant said yesterday.

More than 1000 people were involved in the wild brawl, which began in South Perth as a 30-minute fireworks show kicked off at 8pm.

An alcohol ban was supposed to be in place as a huge crowd gathered along the Swan River to see the annual Skyworks show, but police said those at the centre of the violence were intoxicated.

Police wearing riot gear used pepper spray to break up the crowd. At least two officers required medical treatment.

St John Ambulance volunteers treated more than 300 people during the evening, five of whom were seriously injured.

A spinal injury occurred when a youth dived in the river, and one child was hit by a car after the show.

In total, 77 ambulances were called in to deal with injured people, 54 of whom taken to hospital. This compared with 14 taken to hospital last year.

St John duty commander Jeffrey Williams said he was still stunned by the workload.

"Over half the ambulance cases were assault or alcohol-related," he said. "We've had some Skyworks that have been a bit rough, but nothing like this."

Acting Superintendent John Gillespie said about eight police tried to break up an initial fight between two groups at Sir James Mitchell Park.

"Then all the frustrations from both groups turned on the police officers, who started being pelted with projectiles," he said.

Extra police were sent to the scene, but the numbers hurling bottles and other objects increased, forcing officers to withdraw.

Supt Gillespie said police -- concerned about the wellbeing of the public and St John Ambulance volunteers nearby -- cordoned off the rowdy group.

Police wearing riot gear and using capsicum spray spent more than an hour dispersing the crowd.

There were 22 arrests and more than 750 liquor cautions were issued, along with 60 $50 fines.

Police estimate 300,000 people gathered along the river, in Kings Park, on 1200 boats and at other vantage points to see the annual fireworks display.