Multiple Sclerosis New Zealand is calling for greater access to drugs for patients.

The group says hundreds of people are missing out on life-enhancing drugs, due to Pharmac's strict access criteria.

MS New Zealand vice president Neil Woodham told Tim Dower MS sufferers should be able to access the drugs earlier, and stay on them longer.

"In Australia, where these drugs have been available on a more liberal basis, the number of people with MS of working age who are working has increased by 10 per cent."

He says the drugs can be life changing for patients.

"You ought to allow people with MS, who are on the drugs, to stay on them for much longer than they are currently able to. These drugs have the potential to keep people working for their entire working lives." 

LISTEN ABOVE AS NEIL WOODHAM SPEAKS WITH TIM DOWER