A quarter of people who have chronic migraine, experience it for half the time of the month -- causing severe disability

An Otago University survey has found people have significant levels of pain which can last for days -- leading them to miss out on school or work.

Neurologist Rosamund Hill says there are anti-migraine drugs made available in the last five years, but they're not funded here.

She says they're widely available in the rest of the world, and are publicly funded in Australia.

Hill says the drugs are costing New Zealanders 300-dollars a month.