Gunman dead, officer wounded after shootings at two Sydney police stations

Officers have shot and killed a man outside Penrith Police Station in Sydney's west after he opened fire with a pump-action shotgun.

A man has been shot dead outside a western Sydney police station after he opened fire on officers with a shotgun, injuring one. Source: Nine

A critical incident investigation is underway after a man was shot dead outside a western Sydney police station when he opened fire on officers, ending an hour-long shotgun rampage.

Police say a vehicle stopped outside Penrith Police Station just after 9.30pm on Wednesday and the man approached a police vehicle with a pump-action 12-gauge shotgun and opened fire.

"Police returned fire and the man suffered a fatal injury. He died at the scene," police said in a statement early on Thursday.

Witness footage posted online showed the man falling to the ground after being shot multiple times.

The woman filming the footage from a nearby building can be heard screaming "Oh my God! Oh my God! Oh my God!" as the shots ring out.

Local resident Roy told Nine News he heard the sound of gunfire ring out.

"I heard three loud bangs. It sounded like it was fire crackers," he said.

"You wouldn't think it would happen with a police station right next door."

A male constable suffered pellet wounds to the back of the head and was taken to Westmead Hospital with injuries that were not life-threatening, police said.

Several other officers suffered minor injuries that were not gunshot-related.

The rampage began when the man opened fire on a home on Quakers Road, Marayong, about 8.45pm.

He then drove to St Marys Police Station and fired into that building about 9.15pm.

A critical incident investigation team from the State Crime Command's Homicide Squad will investigate the circumstances surrounding the incident.

The investigation also will be subject to independent review.

Penrith Police Station and St Marys Police Station will be closed until further notice.

Deputy Commissioner Jeff Loy described the shootings as "extreme".

"To shoot upon the police, and wound the police, and force the police to protect themselves and have to return fire is very concerning," he told reporters at the scene.