Facing a lack of the fresh weed for use in traditional Ayurvedic medical preparations, the government ministry responsible wants to be excepted from laws that have made marijuana illegal on the Indian Ocean island since the 1890s.

The Ministry of Indigenous Medicine this month broached a plan to grow 4,000 kg (8,818 lb) a year of marijuana, also known as cannabis, on a proposed 20 acre (8 hectares) farm.

"We are interested in getting some approval to grow some cannabis with government sponsorship, but there must be controls. It is under study," Asoka Malimage, secretary at the Ministry of Indigenous Medicine, told Reuters on Thursday.

Ayurveda is a traditional medicine with roots in the early Hindu era which makes wide use of herbs and natural remedies with the goal of healing the body and mind. In Sri Lanka, ayurveda practitioners outnumber Western-trained doctors.

Fresh marijuana fried in ghee, a form of clarified butter, is used in about 18 different traditional medicines for treating a wide variety of ailments, Malimage said.

"At the moment they are getting some stocks from the courts of law, because there are people who grow this cannabis illegally and they have been raided by the police," Malimage said.

But the problem with that weed is that it is old and dried out, said Dr. Dayangani Senasekara, head of state-run Bandaranaike Memorial Ayurvedic Research Institute in Colombo.

"You can't get the fresh juice from old cannabis. What we get now is the powdered form and it's not effective," Senasekara said.

The institute is making preparations that use marijuana to treat high cholesterol, diabetes, rheumatoid arthritis and skin discolorations, and soon will formulate one for treating cataracts, Senasekara said.

The use of marijuana to treat glaucoma, nausea, pain and the loss of appetite from diseases like cancer and AIDS has been the subject of great medical debate in the west.

Some countries and parts of the United States have permitted its use to treat those conditions, after some medical studies showed it was effective.