The number facing prohibited weapons charges in the regions increased by 20 per cent.
AOS commander Inspector Kelvin Lloyd said more weapons falling into the wrong hands and rising methamphetamine use in the district had created a more volatile criminal environment.
The Otago Daily Times recently reported a mobile meth lab was discovered this year in Invercargill.
"Methamphetamine is a risk factor that we didn't have in previous years,'' Lloyd said.
The rise of meth meant police were using AOS squads more often on searches and other operations.
"It would be one of the higher periods for demand for our services,'' he said.
"There is a tactical option there, in the form of the AOS, if it's needed.
"Everyone is well aware that there are a lot of firearms in the community that have been obtained illegally and that elevates the risk for our squads.
"Everything we are hearing suggests methamphetamine use is on the increase.
"Methamphetamine use is a big concern to us, both in terms of how it affects people in terms of criminality and the health effects that come with it. People on meth are unpredictable.''
He believed the squads, which were part-time and drawn from other areas of police, were resourced to cope with the increase in demand.
Southern police had a large area to cover, he said.
"They have got a substantial rural component and in rural areas there is a higher number of firearms.''
Firearms had been targeted during burglaries. Twenty-three pistols, thousands of rounds of ammunition, four military-style semi-automatic rifles and a shotgun were stolen from a Dunedin address last year.
Members of Hells Angels and the Bandidos motorcycle gang were contacted in regards to buying those stolen weapons.
Police did not keep collated statistics on firearm thefts, but Lloyd said anecdotally there appeared to be an increase.
A recent report by Parliament's Law and Order Select Committee said the primary source for firearms for criminals was stealing them from licensed firearms owners.
"Rural properties are often targeted as a source of illicit firearms because of the high availability of firearms and their remote location,'' the report said.
Firearm ownership rates in the Southern district - New Zealand's largest and most sparsely populated policing district - are some of the highest in the country. Information released under the Official Information Act shows about 10 per cent of residents in the district hold a firearms licence.
Lloyd said law-abiding firearms owners were not the problem.
"We reinforce the safety and security measures and in general, I think, they are pretty good.''
The select committee has made 20 recommendations to the Government to reform gun laws and crack down on illegal firearms. The recommendations are being assessed by two independent advisers and police.