Eleven volunteers were listening for kiwi and morepork at the sanctuary when they saw a spotlight, then heard gunshots in Mopanui Rd about 10pm.
Ecosanctuary general manager Chris Baillie said the latest incident was not a ''one-off'', with spent cartridges found and gunshots heard around the area during the past month.
Volunteers were left a ''little nervous'' from the incident.
They did not feel they would be intentionally shot but worried about the potential for an accident if someone thought they had a deer in their sights and it was actually someone's head torch or reflective tape, for example.
No neighbouring landowners spoken to had given permission, and it appeared those involved were shooting from a vehicle on, or near, a public road.
Volunteers were often in and outside the fence, and were our ''primary concern''.
''We do after-dark tours.
''There could be members of the public in here,'' Ms Baillie said.
Police were called, and while they did not catch those involved, a volunteer managed to speak to a person in connection with Monday's incident.
He said he had spoken to the two young male occupants of a 4WD in Mopanui Rd.
Both men were adamant they had permission to shoot in the area, but apologised for any alarm they might have caused, he said.
Police dispatched a patrol car, but did not find the vehicle involved.
District operations manager Inspector Dave Miller said the incident had the potential to be dangerous, and ''good judgement is the key to using firearms safely''.
Discharging a firearm, airgun, pistol, or restricted weapon in or near a dwelling or public place is an offence under the Arms Act (1983).
Firearm safety
The seven basic rules of safe firearms handling:Treat every firearm as loaded.
• Always point firearms in a safe direction.
• Load a firearm only when ready to fire.
• Identify your target beyond all doubt.
• Check your firing zone.
• Store firearms and ammunition safely.
• Avoid alcohol and drugs when handling firearms.
Source: NZ Police
