It's not just party-goers getting ready to ring in the new year, with emergency services also preparing for a busy night ahead.
"We anticipate a threefold increase to our workload, and most of that is alcohol-related," St John's Doug Gallagher tells 1 NEWS.
They're expecting 500 call outs nationwide during the peak period of 10pm to 2am.
An extra 80 response vehicles and 100 extra frontline staff will be deployed in preparation for revellers partying into the new year.
Paramedic Bryan Dittmer, who has worked the New Year's Eve shift for 25 years, said most of the St John staff are "on the go from the time you start to the time you finish tomorrow morning".
"Most of our staff will be working 12 hours, starting at 6 tonight to 6 in the morning, and then day shift will pick up the bits and pieces tomorrow morning."
Mr Dittmer said to look after your friends if they've had too much to drink, with staff often finding people in trouble being left on their own.
"It's just been a well-meaning member of the public passing by that's dialled 111 and we arrive to find the person alone. They've essentially been abandoned."
Emergency departments are also preparing for a big night by rostering on extra staff.
Last year, Auckland DHB treated more than 350 patients on New Year's Eve.
Police are hoping to get those numbers down this year by urging revellers to leave their cars at home.
"[There will be] quite a visible presence on the main roads, on the motorways and in the main cities," said Auckland City East Police Inspector Jo Tipene.
"We just want to wish everybody a happy new year and a safe and merry 2019. Enjoy the festivities that tonight will bring, but yeah, we just want people to be safe and happy tonight."