Intellectually disabled woman sexually assaulted in Sydney's west

A 21-year-old woman with an intellectual disability has been sexually assaulted in Sydney's west.

Police said a man tried to strike up a conversation with the woman before assaulting her about 8pm on Tuesday in Bossley Park.

The attack happened near the entrance to the T-way bus lane close to Wheller Street, police said.

Police described the perpetrator as aged in his mid 40, of Middle Eastern or Mediterranean appearance with fair skin. He was wearing a grey hooded jumper.

Detectives from Fairfield Local Area Command are investigating.

Anyone with information should call Fairfield Police or Crime Stoppers on 1800 333 000.