A young police officer has been rushed to hospital after allegedly being knocked unconscious in the street in Sydney.

NSW Police said the 23-year-old female officer was responding to a mental health incident about 6.30pm on Friday in Bidwell, in Sydney’s northwest.

A separate police patrol found the officer lying “unresponsive” on Bunya Rd after being called to reports of a injured officer.

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Police said two female officers from the Mt Druitt area command had been assaulted at the scene.

The 23-year-old was treated at the scene by first responders and paramedics before being transported to Westmead Hospital in a stable condition.

A second officer — a 22-year-old woman — was also treated at the scene and was taken to Mount Druitt Hospital as a precaution.

A 19-year-old man was arrested by police at the scene and was later taken to Nepean Hospital.

Inquiries are ongoing and anyone with information is urged to contact police.