Police have charged more than 100 people with drug offences during a dance music festival in Sydney.

On Saturday 565 people were searched at Stereosonic, which is running all weekend at Olympic Park.

Officers seized illegal drugs including cannabis and ecstasy tablets, and a total of 105 people were charged with drug-related offences.

Thirteen people were charged after allegedly bringing alcohol into the venue, while four people were also arrested over alleged assault incidents.

More than 200 officers are at the event, which is attended by around 58,000 people each day.

Superintendent David Eardley says officers have stepped up their efforts in response to fatal overdoses at other festivals earlier this year.

"We've made a concerted effort this year," he said.

"When you look at recent events that have been held in Sydney when you've had people overdose and die on these illicit substances, we have to take these things seriously.

"And our resourcing commitment to this event is I think reflective of that."

Police also arrested and charged 11 people while conducting a drug dog operation at Central Railway Station, which targeted revellers on their way to the event.