Parts of Castlereagh Road in Penrith were shut down this afternoon, with a gunman eluding a massive police pursuit.

The operation began at Carpenter Street, Colyton, where a white SUV, believed to be stolen, was stopped by police.

The driver allegedly produced a gun and drove away, and the vehicle was found abandoned on Hanlan Street, Cranebrook.

A 22-year-old female was arrested after a foot pursuit in the adjoining Soling Crescent.

A search is underway for a male, armed with a gun, who is believed to have fled the vehicle into nearby bushland.

Listeners in the area report dozens of police vehicles on the scene, including the riot squad, dog squad and multiple PolAir aircraft circling.

Reports of shots fired are not accurate, police have confirmed.

In vision circulating on social media, police can be seen confronting the driver, ordering him to drop his weapon.

Seven News crime reporter Evan Batten was on the scene in Penrith, and told Jim Wilson with the sun setting, the search is now winding down.

“They’ve really scaled back the search.

“Unfortunately, at the point, he has managed to elude them.”

Press PLAY below to hear the latest from the scene