Man stabbed while saving girl from sexual assault

A man has been stabbed while trying to stop a seven-year-old girl being sexually assaulted by another man in a toilet at a dance studio in Sydney's south.

It's believed the 54-year-old assaulted the girl in the studio's toilet on Railway Parade in Kogarah on Thursday night.

A 46-year-old who confronted the alleged offender was stabbed in the abdomen and neck during a struggle.

The male victim was taken to St George Hospital in a stable condition. The girl was taken to Sydney Children's Hospital for observation.

The alleged attacker was arrested and taken to hospital with facial swelling and bruising. He remained under police guard and was due to be interviewed on Friday evening.

Police Superintendent Julian Griffiths said the man - from Kogarah - was not a staff member or known to the dance studio.