A man has been charged with possessing ammunition, following an Armed Offenders Squad callout in Lower Hutt last week.
But police were still trying to find guns which they suspect were also used last Thursday.
Officers had responded to witness accounts of a man carrying a gun.
They sealed off roads around Harrison Crescent during their callout and detectives said they found a stolen car.
A 31-year-old man will appear in Hutt Valley District Court on 28 January.