A girl, 13, has drowned trying to save her younger brother who got into trouble in the surf at a southeast Victorian beach.

The girl and her father went into the surf to help the 11-year-old boy at Williamsons Beach near Wonthaggi about 8pm on Thursday.

The boy was saved and taken to Monash Medical Centre to be treated for injuries, but tragically his sister was swept out during the rescue effort.

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“Whilst the boy received only minor injuries requiring hospitalisation, the young girl also got into trouble and consequently died despite efforts by her family, police and ambulance officers trying to save her,” a Victoria Police spokeswoman told the ABC.

Paramedics reportedly spent over an hour trying to revive the girl at the notoriously dangerous swimming spot.

Life Saving Victoria spokesman Paul Shannon told 3AW radio the beach was “extremely hazardous” and not patrolled by life guards.

“It’s a straight-out tragedy that’s happened to a family that’s probably gone down to have a fun day at the beach,” he said.

“Our hearts just go out to this poor family who have lost a child and have another one in hospital.”

A report is being prepared for the coroner.