Police are looking for an armed robber who stole money at gunpoint from a south Auckland dairy.

The robbery happened around 7pm on Great south Rd, near Grandevue Rd.

"A man had entered a dairy and presented a gun and left with cash," a police spokeswoman said.

The offender was still on the loose but police had a description of what he looked like and were actively searching for him.

Police were working to support the staff member on duty at the time of the robbery.