A man has been shot by police after allegedly ramming an officer between two vehicles with a reportedly stolen car in Sydney’s south-west.

Public order and riot squad officers came across a Toyota C-HR — reportedly stolen from Riverwood — on Juno Parade in Punchbowl about 8:40pm on Wednesday.

When an officer attempted to arrest the driver at the intersection of Punchbowl Road, the vehicle accelerated, pinning him between two cars.

An up close of a car windshield with three bullet holes.

The vehicle had multiple bullet holes in its windshield. (ABC News)

The officer fired his gun at the Toyota before it drove off.

Paramedics treated the 39-year-old officer for injuries to his lower leg and he was taken to hospital in a stable condition.

Just after 9:15pm police were called to Thorn Street at Ryde following reports an injured man had been seen walking along the street.

Police said a stolen Toyota was located on Richard Johnson Crescent shortly before a man suffering a gunshot wound was found in the yard of a nearby home.

The 32-year-old man was taken to hospital in a stable condition where he remains under police guard.

Separate officer assaulted at emergency department

Meanwhile, emergency services were called to Campbell Hill Road at Chester Hill about 11:30pm following reports shots were fired from one car into another.

Both vehicles left the scene before police arrived.

At about 11:35pm, a 26-year-old man presented at Auburn Hospital with gunshot wounds to his leg.

Forensic officers scour for evidence at the scene of a shooting.

A 26-year-old man is in critical condition after presenting to hospital with a gunshot wound. (Supplied)

Officers attended the hospital and located a Mercedes in the car park with a number of bullet holes and a crime scene was established.

Police said officers attempted to speak with a 30-year-old man in the emergency department when he allegedly repeatedly punched a 58-year-old chief inspector, causing lacerations to his head.

The man was arrested and taken to Auburn Police Station where he was charged with assaulting a police officer in the execution of duty.

The 26-year-old injured man has since been transferred and remains in a critical condition.