Rifles, ammunition and other equipment were confiscated and the poachers were charged with firearms offences.
Senior Constable Murray Hewitson, of Owaka, said there was often a spike of dangerous and irresponsible hunting activity around the roar - the March-April rutting season when deer are less cautious than other times.
Most instances of poaching involved night-time trespassing on private property and shooting from public and forestry roadsides. Incidents had been reported around Lawrence and the Catlins.
Snr Const Hewitson said poachers were putting lives at risk.
"It's extremely unsafe and someone will end up getting hurt," he said.
"There are plenty of hunting opportunities available through the legal permit and block ballot systems, and farmers often have a problem with deer, so if people want to hunt on private property they should just ask permission."
Charges related to unlawful hunting and the Wild Animal Control Act are strict, beginning with seizure of equipment including vehicles, loss of the firearms licence, fines of up to $100,000 and a two-year prison sentence.
Stalkers looking for game in the same area without knowledge of each other were in danger of becoming each other's targets, police said.
It was impossible to safely identify targets and check firing zones when shooting under the cover of darkness.
