Police think the same man using a gun is behind a pair of robberies on Auckland's North Shore.

The first happened on July 15 in Torbay at a Mobil petrol station.

The man filled a petrol container before pulling a balaclava over his face and pulling a pistol out.

He demanded money and cigarettes.

A man fitting the same description went into a dairy also in Torbay yesterday with a pistol, and also demanded cash and cigarettes.

Police say even though the man's face is covered in security video, people might recognise his body movement and clothing.

They say they want to stop the man as soon as possible.