Invercargill police have released CCTV footage of three men who held up a cash transit van outside ANZ Bank on Wednesday.
A police spokesman said during the incident, which began at 9.13am, a man threatened a security guard with a taser, while a second man pointed a sawn off firearm at another security guard.
Police would not comment on how much money was taken, other than saying it was a “substantial amount”.
“Police are seeking information on anyone with large amounts of cash in various denominations including $100 bills, or anyone who behaved suspiciously before or after the incident.”
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Police were also interesting in anyone with information relating to the distinctive overalls, gloves and footwear worn by the offenders.
After the robbery, the men left in a dark green and silver Subaru vehicle, which was later recovered in a carpark on Leven St.
Witness to the robbery, Heather Raywyn Park said she was walking along Kelvin St towards the ANZ when the armed robbery unfolded.
She saw what she thought was a black with silver Subaru Legacy drive up and three men dressed in black with firearms and what appeared to be a taser, Park said.
The men assaulted the guards, taking bags from the armoured van before making their getaway heading south on Kelvin St, she said.
The armoured transport company ACM did cash pickups and drop-offs for the bank.
One of the guards suffered minor injuries during the robbery.
Anyone with information should contact Invercargill police on (03) 2110400 or Crimestoppers on 0800 555 111.