Woman under guard after Sydney smash

A woman is under police guard in hospital after a three-car prang in Sydney's inner west.

Crash investigators believe the 34-year-old ploughed into the back of a car travelling in the same direction on Parramatta Road in Camperdown about 1am on Saturday.

She then smashed into a stationary taxi, police believe.

The woman was taken to hospital with minor injuries, where she remains under police guard.

The drivers of the other vehicles were assessed at the scene but did not require further treatment.