Just one in 100 people with Multiple Sclerosis (MS) in Northern Ireland are using two treatments which can reduce painful muscle spasms and improve walking, it was revealed.
The MS Society claimed people with the incurable neurological condition face a care lottery.
But the Society said a higher proportion of people in the region are taking disease-modifying therapies compared to the UK average.
Stand-in Northern Ireland director Tom Mallon said: "We want to ensure that people access their treatments when they need the treatments and no matter where they live."
He said implementing the Society's recommendations for change meant the difference between destroying or enriching life.
"People with MS and their carers still face many unnecessary barriers in terms of accessing the medicines which they require. This must change."
Northern Ireland has one of the highest rates of MS in the world, affecting approximately 3,000 people or 1 in 500.
The disease damages the central nervous system but drugs can slow the progression of disability and treat the symptoms.
It is caused by damage to the myelin sheath, which surrounds the nerve fibres. There are many symptoms, including vision and balance problems, spasms and stiffness.
The Society held an event at Stormont attended by many with the condition. The Society conducted a survey of those affected to inform a new report.