Thousands of children competing at a major swimming carnival have been evacuated after solar panels on the roof of Sydney's Olympic Park aquatic centre caught fire.
Six fire trucks and 24 firefighters rushed to the scene at Homebush, in the city's west, after reports of thick black smoke billowing from the building about 12.15pm on Monday.
Up to 2000 children attending the NSW combined high school carnival were forced to evacuate the aquatic centre, some in their swimming costumes.
Firefighters used a ladder platform to attack the flames, containing the blaze in about 45 minutes.
"More than 2500 people have been safely evacuated from Sydney Olympic Park Aquatic Centre in Homebush following a solar panel fire," Fire and Rescue NSW said in a statement.
There were no reported injuries.
Witnesses told Sydney radio 2GB hundreds of children, including some in their costumes, were seen running from the building's rear entrance while the roof was ablaze.
NSW Fire and Rescue spokesperson Adam Dewberry said there could be a number of reasons why the solar panels ignited.
"There is pretty extensive damage," he said.
"It did burn free for a period of time but we were able to get on top and contain it.
"We've had hundreds of people safely evacuated with no injuries reported, so it's a great outcome so far."
The swimming championships, which involve students from around the state, featured about 2000 people competing.
Hundreds of children are still trying to get back inside to collect their belongings.
A NSW Ambulance spokesman said three ambulances were on the scene with one patient assessed for a hip injury.
Investigations are under way to determine the cause of the fire.