Eight people with gang links spent the night in custody after throwing a party against lockdown rules.
Police say the property in Kowhai Tce, Christchurch, was booming by the time officers arrived on Friday night.
Senior Sergeant Paul Robertson says the scale of the party drew attention to itself.
"We were called by a member of the public who said that there was a party going on," he told Newshub.
"They found that there was a party going on - staff have gone in and found people there that were breaching the restrictions.
"From the staff who have turned up, it was pretty obvious that some people there [the party] did have gang links."
Snr Sgt Robertson says people need to remain patient through alert level 3.
"There were several small gatherings or parties around the city [Christchurch] last night but we got to the ones we could and any others that we didn't, as I said, they'll be getting followed up later on."
On Friday afternoon, Finance Minister Grant Robertson fired a warning to Kiwis after reports people were having house parties under alert level 3 restrictions.
"I have two clear messages for anyone considering [attending a house party]. First, cancel your plans now," he told reporters. "Secondly, be aware that the police will be particularly taking a dim view of this activity as part of their level 3 enforcement activity this weekend."
