Police say the AOS was sent to a Stewart St house about 1am, as a precaution, after a man threatened to use a firearm during an altercation outside the Rosebank Lodge several hours earlier.
Sergeant Martin Bull said police used the squad to help execute a search warrant at the house.
No firearms were found.
Sgt Bull said police were called to the hotel about 1am to deal with a fight between two groups.
"During this fight, one of the parties has talked about getting a firearm out of the boot of his car."
Police attended but the "main protagonists" had left before they arrived.
About 2.30am there was another fight, this time outside a Stewart St house between the same groups.
Police were able to calm the situation and dealt with the incident then, Sgt Bull said.
When police returned to the house about 11am, armed with a search warrant and the squad, neighbours were told to keep inside and the street was cordoned off.
A 28-year-old Invercargill man was arrested and charged with giving false details, disqualified driving and for an outstanding warrant issued for breaching his parole conditions.
He will appear in the Dunedin District Court this morning.
Sgt Bull said a 32-year-old Kaihiku man was also arrested and charged with disorderly behaviour likely to cause violence.
He will appear in the Balclutha District Court on Tuesday.
Police want to speak to anyone who witnessed either incident early yesterday morning
