An alcohol expert warns New Zealand has reached 'peak booze' - and some the worst affected are older generations.

New statistics show the damage alcohol is doing to New Zealand as problem drinking cuts a swathe through our elderly. And the problem is getting worse.

"One-third of NZ's hazardous drinkers are now aged 35-54," says Alcohol Healthwatch executive director Dr Nicki Jackson.

"For the older groups, hazardous drinking is now higher than it was back in 2006/07. It feels like we have a new 'peak booze' among parts of our population."

The Ministry of Health estimates that over 780,000 adults are hazardous drinkers. Statistics NZ figures show the drinking habits for more than a third of people aged 18-24 could be potentially hazardous - regularly consuming six more drinks in a single session.

Dr Jackson warns there's been an increase in hazardous drinking every year since 2011, and says it's increased by more than 50 percent among those aged 45 to 64 years.

As well as this, hazardous drinking in the 66-74-year age group more than doubled from 2011/12 to 2015/16.

"Our older drinkers are some of the heaviest drinkers in the world," she says.

This drinking has a chilling effect our health system. During the 2016-2017 financial year, 4070 people were hospitalised due to their alcohol consumption - some more than once.