Newshub can reveal 8.6 percent of Kiwis have used antidepressants over the past year.
Experts Newshub spoke to suggest the use of medication instead of therapy could be used to cut costs.
- Antidepressants really do work - study
- Antidepressants may reduce risk of second heart attack - study
- Dozens of genetic variants for depression discovered - all humans carry some
Data obtained by Newshub shows in 2016 there were 409,800 patients. In 2017 there were 422,500 and in 2018 there were 425,700.
According to Stats NZ, New Zealand's population is 4.9 million.
New Zealand's population grew 1.9 percent in the June 2018 year, down slightly from 2.1 percent in 2017.
The number of antidepressants prescriptions has also grown over the same time period.
New Zealand Medical Association Chair Kate Baddock revealed the state of mental health in New Zealand is shocking.
"It's disastrous. Increasing levels of mental distress, mental illness and limited means for managing and addressing it," she said.
Ms Baddock does think the Government takes mental health seriously, but says better funding is needed to allow people to access more options.
"We need a better way of delivering the services that people need. We need to be able to do it in a way that's affordable and accessible. We don't have that currently," she said.
"What we do have are funded medications that are not inferior to those other treatments, but neither are they better. We should be using non-medical treatments if they are as good, but they cost too much."
New Zealand Association of Counsellors spokesperson Christine Macfarlane explained to Newshub there is a positive to take from the increase.
"I think there's been a lot of education and coverage around depression and anxiety which means there is a likelihood of more people seeking treatment," she said.
"People will know more about antidepressants and are looking to have a treatment that works."
But she says the system is underfunded and the problem is at crisis point.
"I think we're missing the in-between part. Across the country we have [primary health organisations] providing brief intervention which is around 4-6 sessions of counselling or therapy or support.
"If someone has got depression or long term anxiety, that's not enough time for them to come out of that. We really need to be looking at a service that can stick around and support people for 6 months or a year."
Newshub can also reveal the top five DHBs with the most patients using the funded medicines listed under the Antidepressants Therapeutic Group in 2018.
Canterbury is in the lead with 74,300, followed by Waitemata (57,900), Waikato (50,000), Auckland (48,500) and Counties Manukau (43,700).
Ms Macfarlane isn't surprised by the statistics.
"They are some of the more stressed areas. Canterbury will be having on-going post-traumatic stress disorder and depression after the earthquakes. It doesn't just stop when the earthquakes stop," she said.
"Waitemata, Waikato, Auckland and Counties Manukau would be the pressure of living in cities, the difficulty in housing, social structures, high poverty, unemployment. All of those things contribute to mental health disorders and struggles."