Woman who stopped Adelaide beach brawl speaks out

A woman who tried to break up a public fight between two people at an Adelaide beach has described having bottles thrown at her by onlookers.

Premier Peter Malinauskas has described the fights as "unacceptable" amid ongoing investigation by SA Police.

A police operation to prevent crime along Adelaide's coast has begun.

A woman who tried to stop a brawl on an Adelaide beach before being pelted with bottles has spoken publicly for the first time.

Earlier this week, videos emerged online of several fights at Glenelg and Henley Beach on Tuesday, with hundreds of teenagers spectating.

In several clips, a bystander tried to break up two males wrestling at Glenelg Beach, but she was hit with bottles and copped boos when she stepped up.

Kate, whose name we have changed for her safety, is sharing her experience for the first time since that footage circulated online.

She was at the beach with her daughter and her friend when she first noticed dozens of people running toward a gathering, which she soon realised was people watching a fight.

Kate has spoken of having bottles thrown at her by onlookers. (ABC News: Lincoln Rothall)

"I wasn't thinking, really. I just thought, 'I've got to try and stop this'," she said.

"It was so loud … we're not talking 50 kids here, we're talking 200.

Kate said she felt she had no choice but to try and protect other beachgoers.

When she broke up the altercation, the fighters got up and told her they were "mucking around".

But she said the crowd egged on the violence.

"No-one could probably really hear me in the end because there was so much booing happening," she said.

Kate said the situation escalated when several bottles were thrown at her direction, leaving her with bruises.

"Then the other one threw something at me, and I did pick up the bottle, and I said: 'Enough'. I was doing my mum's voice," she said.

"What scared me too [is] there was a mother with little kids sitting right at the front."

The mother said she had reported it to police.

On Wednesday, SA Police said it was looking to identify the "level of organisation" behind the fights and find those responsible.

As of this morning, no charges had been laid and the investigation remains ongoing.

Police said they were called after large crowds gathered at both Glenelg and Henley Beach, but most people had scattered by the time they arrived.

In the wake of recent incidents, a police operation to prevent street crime and public disorder along Adelaide's western beaches, originally planned to start at the end of the month, was brought forward to today.

SA Premier Peter Malinauskas on Thursday condemned the fights but said government cannot "eradicate idiocy".

"When young people decide to beat each other up, it is completely unacceptable behaviour and we should all be uncompromising in our desire to see it leave our society," he said.

Police Minister Michael Brown today vowed police would maintain a strong presence over summer.

However, it is not enough peace of mind for Kate, who said she will avoid busy beaches during the hotter months.

Fights at Adelaide's beaches were shared on social media and are now the subject of police investigation. (ABC News: Lincoln Rothall)

"I just don't want my daughter to see stuff like that either … it's not good," she said.

Kate had a serious message for the people fighting too, warning they could have been seriously injured.

"These kids have got to think before doing anything," she said.