The St John ambulance service is putting on more than 100 extra frontline staff and 80 more vehicles nationwide to cope with the expected demand over New Year's Eve.
A director of clinical operations said 111 calls typically increased three-fold at this time and were mainly alcohol related.
Norma Lane said the busiest time was between 10pm and 2am, when the service was likely to respond to around 500 calls.
She said more than a third of calls on New Year's Eve were alcohol-related, with people passing out, assaults, traumatic injuries and motor vehicles crashes making up more than 30 percent of ambulance call outs.
St John assistant director of operations Tony Devanney said having to deal with intoxicated people could be difficult for frontline staff.
"Intoxication and substance misuse contributes hugely to falls, injuries and assaults. St John ambulance officers are caring and non-judgmental professionals who are there to help, but trying to treat someone vomiting over you, attacking you or being so incoherent or unconscious that the patient can't explain what is wrong, complicates treatment and is not ideal."
Ms Lane said the service was asking people to drink sensibly and to look after their friends.
"Don't leave an intoxicated person on their own," she said.
She also advised people to have a plan on how to get home before heading out.