More and more Kiwis need their morning coffee kick-start, with 44 per cent saying they need a caffeine hit each day.
Conducted by Canstar Blue, a survey of nearly 2000 people found more women than men suffer from caffeine withdrawal symptoms.
Headaches and dizziness are associated with withdrawals, which could be why a quarter of women surveyed said they were trying to cut down their intake.
"Coffee has been New Zealand's most popular hot drink since the 1980s so it's no wonder so many of us have come to depend on it for a kick-start in the morning," Canstar Blue spokeswoman Emma Quantrill said.
In 2015 Canstar Blue found 42 per cent of Wellingtonians couldn't start their day without coffee. Aucklanders spent on average $14.02 a week, but of concern was 15 per cent said they've had so much coffee in a day they haven't been able to sleep.
Quantrill said Kiwis' affinity for coffee over tea gave them that extra kick to get their day going, however, people need to be careful not to have too much.
"There's a lot more caffeine in coffee than tea and it's this element that gives our brains the shove we sometimes need in the morning.
"The flip side, as many of us know, is we've got to be careful with our afternoon double shots or after dinner coffee as it can give an energy boost that stops us getting a restful sleep."
Caffeine is a central nervous system stimulant which is found in tea, cocoa, energy drinks and many soft drinks. It increases energy alertness, motivation and concentration, but can induce dizziness, increased heart rates, irritability, anxiety, tremors and insomnia.
The New Zealand Food Safety Authority estimates over 73 per cent of New Zealanders are exposed to caffeine in their diet.
"For those of us who like to make ourselves coffee first thing in the morning, we often have a larger than average cup or give ourselves a refill, which is obviously far more than what you expect in an average cup."
Quantrill said people should take into consideration what coffee they drink, as instant coffee can have 50 per cent less caffeine than filtered coffee. Lightly roasted coffee beans are also believed to have high levels of caffeine when compared to darker varieties.