Wainhouse said police guarded the scene overnight and forensic officers carried out an examination on Monday. Police are reviewing CCTV footage from the premises.
The vehicle used in the raid was stolen earlier in the evening from Surrey Rd and was later recovered in Rapanui Rd. It was a silver Mazda Familia, registration CMY543.
"We are interested in hearing from anyone who saw that vehicle from the time it was taken or who may have seen it being dumped in Rapanui Rd," Wainhouse said.
Anyone with information can contact Whanganui Police on 349 0600 or Crimestoppers anonymously on 0800 555 111.
Whanganui has suffered at least 13 aggravated robberies in the last year:
Sunday, March 25 - 7.30am: A 23-year-old male armed with a hammer robbed the Abbot St dairy, taking cigarettes. He later handed himself in to police.
Saturday, November 18, 2017 - 1pm: Two males armed with weapons (not guns) rob the Hospital Shop in Heads Rd, taking tobacco products.
Thursday, November 09, 2017 - 9pm. Three offenders, one armed with hammer, rob sole staff member at Black Bull Liquor store and get away with cigarettes, alcohol and a small quantity of cash.
Tuesday, November 7, 2017 -- 8.55pm: Three men (faces covered) — aggravated burglary BP service station, Whanganui East — stole cash and cigarettes. Fourth offender drove dark coloured three-door Mazda hatchback.
Sunday, Oct 29, 2017: Four arrested (including three youths) and charged with aggravated robbery of Caltex Service Station, Victoria Ave. A substantial amount of property recovered.
Friday, Sept 22, 2017: Two men , one armed with knife, rob Z service station, Dublin St -- took tobacco and cash.
Saturday, Sept 9, 2017: Four thieves, 18-20, 3 inside; one outside. Demand ciggies and cash; steal food from Rangitikei St dairy. Hammer attack on heads of Mr Zhou and one woman.
Saturday, Sept 9, 2017: Two youths enter Polson St dairy, Castlecliff, demand ciggies and cash; smash counter with hockey sticks. Two referred to Youth Aid.
Sunday, May 21, 2017: Armed robbers held up the Springvale dairy in Fitzherbert Avenue leaving the owner injured and in shock. It is alleged two offenders, one armed with a firearm and the other with another weapon, stole cash and cigarettes -- TWO ARRESTS.
Wednesday, May 3, 2017: Castlecliff Hotel held up at gunpoint -- TWO ARRESTS
April 27, 2017: Four offenders entered the McDonald's restaurant on Liffiton St and demanded money before fleeing across State Highway 3 ONE ARREST.
April 18, 2017: Four offenders use a small red Mazda car to smash through the roller door of the Castlecliff Camp Store, Rangiora Street. Money taken.
December 13, 2016: Four armed offenders entered the BP Connect service station on London Street and made off with cigarettes TWO ARRESTS.
December 11, 2016: Three offenders took alcohol and cash as well as cigarettes from the liquor store in Purnell St.
See also:
Gull Gonville ready to fly