Sisters attacked by a sexual predator in public toilet block

A SUMMER picnic in the park has changed the lives of two parents forever after their young daughters were attacked by a sexual predator in a public toilet block.

Police have been told the park at Guilford, in Sydney's west was buzzing with people on Thursday when a six-year-old girl took her two-year-old sister to the bathroom.

While they were inside a man sexually assaulted them both.

Detectives from the child abuse have expressed sorrow for the girls' "very good parents", who had the right to believe their children would be safe in the middle of the day on school holidays with people around.

Child Abuse Squad Acting Superintendent Peter Yeomans told the Herald the girls had been treated in hospital and were "very upset" by what had occurred.

The wanted man is described as being of Middle Eastern/Mediterranean appearance, aged 20-30, about 165cm tall with an average build and facial hair. He was last seen wearing black hooded jacket and blue shorts or pants.

Helicopters and the dog squad were called in to search the area for the man on Thursday but he was not found.

Strike Force Sandyman has been established to track him down.

Anyone with information can phone Crime Stoppers on 1800 333 000.