Senior Sergeant Craig Dinnissen said police were called to a Castle St property at 12.30am by noise control.
They arrived to find more than 100 intoxicated students breaching Alert Level 4 lockdown rules.
Police dispersed the crowd and a 20-year-old resident was issued a warning and educated about lockdown rules.
People were seen queuing out the door of a liquor store in Leith St last night.
Meanwhile, a 32-year-old woman was pulled over on Stevenson Rd and found to be driving with a breath-alcohol level of 600mcg.
She had been drinking at home, but due to the lockdown announcement wanted to buy more alcohol.
The breath alcohol limit for drivers aged 20 or over is 250mcg. There is a zero alcohol limit for drivers under 20.
In a statement today, police said they would have a highly visible presence throughout the country to ensure awareness of the level 4 restrictions.
"Our absolute priority is ensuring New Zealanders are safe and supported, and our focus will be on engaging, encouraging and educating.
"However, police expect people are by now well aware of what is expected of them and they are asked to follow the rules. People can expect the Alert Level restrictions to be enforced."
