Health experts are calling on district health board bosses to cover Botox treatment for people suffering from chronic migraines.

They say many New Zealanders battling chronic migraines are finding relief with Botox but for those living within the catchment of Auckland's DHBs, it's costing them each a small fortune.

Trish Wakelin, 49, is among them. She pays $1000 each month to keep her migraines to a minimum.

She says she can't afford to keep getting Botox and will soon be out of options leaving her in severe pain.

"My husband and I are meant to be saving for a home after our last one got destroyed from leaks ... I'm spending money on my head instead of saving," Wakelin told the Weekend Herald.

The United States' Food and Drug Administration approved Botox for chronic migraines in 2010 after a clinical trial showed its effectiveness. Australia then followed suit funding the treatment for patients who had tried other methods and had no relief.

Pharmac director of operations Lisa Williams said Botox was funded for use in DHB hospitals and there were no restrictions on what it could be used for.

"It is used by DHB hospitals for inpatients and in outpatient clinics to treat a variety of issues – including chronic migraines," Williams said.

Auckland neurologist Dr Rosamund Hill said that for a long time Auckland DHBs had refused to fund Botox for migraines due to a tight budget.

"There is no separate funding so it's a bit of a loophole. I'm in the process of putting together a budget proposal to help the Auckland DHBs see it's viable," Hill said.

Former finance manager Trish Wakelin found herself struggling to add basic maths, stumbling and passing out from migraines - her only relief is Botox. Photo/Dean Purcell

An Auckland DHB spokeswoman confirmed Botox was funded for treatment in hospital.

"We currently use Botox to treat muscle spasm disorders in our hospitals, but not migraines.

"Hospital-based migraine management with Botox would require new infrastructure, so would need to be looked at very closely," the spokeswoman said.

Hill said chronic migraines most commonly affected people in their 20s, 30s or 40s.

"It's the workforce who are being debilitated. That's a huge loss of earning because many of them can't work with chronic migraines - we should be making sure people are well enough to work," Hill said.

For Wakelin, she was at the peak of her career when her life was flipped upside down.

The finance manager found herself struggling to do basic maths, stumbling as she got on and off the bus and often passing out from "unbearable pain".

"It felt like someone was smacking my head with an axe," Wakelin said.

After several hospitalisations, Wakelin was forced to give up the job she loved.

"From being able to work at that highest level and look after the financials of a top national company to not being able to literally add two, three and four together was hugely frustrating," Wakelin said.

Getting a migraine meant Wakelin was often left unable to walk, talk or function properly.

"I do think people overlook the severity of migraines ... it's not until a neurologist is picking you off the ground of the emergency department that the seriousness kicks in," Wakelin said.

She tried a number of Government-funded treatments including infusions called Dihydroergotamine (DHE), a drug called Triptan and epilepsy drugs but all came with "brutal side effects" such as nausea, vomiting, and "feeling not all there", Wakelin said.

Then she discovered Botox. Since October last year, she has been getting monthly injections in the back of her neck and around the crown of her head.

"The impact has been massive - I don't get the side effects I did from other treatments and I'm now looking to return to work," Wakelin said.

And she's not the only one.

Auckland Botox specialist Dr Cat Stone said she treats hundreds of people each year for chronic migraines.

Auckland Botox specialist Dr Cat Stone gives migraine sufferer Trish Wakelin her monthly dose of relief. Photo/Dean Purcell

"It's heart-breaking to know Botox might be the only option to stop the pain but for some the cost is out of reach.

"I'd just love to see Trish able to function properly and get back to work without it causing a financial strain on her," Stone said.

What are chronic migraines?

Migraines are intense pulsing or throbbing pain in one area of the head. The Neurological Foundation of New Zealand says sufferers may also be extremely sensitive to light and noise and experience nausea and vomiting.

The International Headache Society defines chronic migraines as more than 15 headache days per month over a three month period, of which more than eight are migraines.