A small number of children with drug-resistant epilepsy will soon be able to access a new cannabis-based drug in New South Wales which is showing promise in relieving the symptoms.

The pharmaceutical drug, Epidolex, is still in a trial phase and has not yet received full approval from authorities, but the Government has now set the date of March for a compassionate access scheme to begin.

Last year, the NSW Government approached the company that makes the drug, the UK's GW Pharmaceuticals, to see if trials could be arranged in NSW.

Pru Goward, the Minister for Medical Research, said the scheme was great news for families who had children with the condition.

"These families are desperate," Ms Goward told the ABC.

Medical Research Minister Pru Goward says the scheme is great news for families. ( AAP: Dean Lewins )

"When children fit dozens, hundreds of times a day, they often develop brain damage.

"They certainly have a very interrupted life, they can't read or write, they find it difficult to go to school.

"They can't play with other children because this condition is so debilitating."

GW pharmaceuticals said the drug, which had been trialled internationally, could be administered without the psychoactive effects of smoking marijuana.

Current medication used to treat epilepsy can leave children to deal with unwanted side effects, including an inability to regulate body temperature and negative effects on memory or liver functions.

The use of Epidolex is part of $3.5 million batch of trials announced by the NSW Government in partnership with GW Pharmaceuticals, which includes a world-first trial of another drug, CBDV, or cannabidivarin.

New South Wales is also conducting a medicinal marijuana trial for adults with a terminal illness - the Terminal Illness Cannabis Scheme.

Ms Goward said that should the drug be approved, she was confident it would be available for use in Australia within three years.

The compassionate access scheme will start in March.