A man has been shot several times while sitting in a car in Sydney's southwest.

Two men were sitting in a car on Australia Street, Bass Hill, about 1am (AEDT) on Sunday, when another car pulled up behind them.

One of the men in the rear car shot the passenger of the front car several times, police say.

The 37-year-old man was taken to hospital in a stable condition.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000.