Police are searching for a man believed to be involved in an aggravated robbery of a pharmacy in Whanganui last night.

Whanganui Police were called to Radius Pharmacy on Fitzherbert Avenue Shopping Centre around 6.15pm on Saturday where a man entered the store armed with a weapon and demanding medication.

He then fled on foot towards Parson Street towards Kohini Street.

The accused is described as a Caucasian man, about five-foot tall and of slight build.

Detective Aaron Bunker says the man was wearing a dark top and black pants at the time of the robbery and has been described as being quietly spoken.

Police want to speak with the occupants of a white Nissan Maxima, possibly a 90's model, which was seen in the Parson Street/Konini Street area at around 6pm on Saturday.

Anyone with information is asked to contact Aaron on 06 3490638. Alternatively, information can be provided to Crimestoppers on 0800 555 111.