Girl, 11, missing in Sydney's south

Julia Carlisle

An 11-year-old girl has gone missing in Sydney's south, with a large-scale search involving the police chopper and the dog squad out looking for her.

Jacinta Laverance, a keen runner, was reportedly last seen at her family home on Amaroo Street in Sylvania Heights on Sunday night wearing her purple and aqua pyjamas.

Police say her parents woke on Monday morning to find her missing.

NSW Sutherland Police Area Command Chief Inspector Chris Hill said Jacinta's parents noticed her running shoes were also missing on Monday morning so they went to the local athletics track thinking she may be there.

Her parents reported her missing about 7.30am on Monday, saying her disappearance is out of character.

"At this stage we can't identify any reasons why she left home," Insp Hill told 2GB Radio on Monday, adding that Jacinta had not shown up for school either.

Inps Hill said no other clothing appeared to be missing, so police were searching for Jacinta under the assumption she was still wearing her pyjamas and her missing running shoes.

Jacinta, reportedly one of four children, is about 172cm tall, with a slim build and blonde hair.

Anyone with information is urged to call triple-zero or Crime Stoppers on 1800 333 000.