The Royal Project Foundation is looking into developing strains low in the substance that produces the effects of the drug cannabis.

The project follows a suggestion by Her Majesty the Queen that highland people could cultivate hemp to make garments.

Foundation president MC Bhisatej Rajani said industrial hemp had the potential to be a valuable cash crop.

However, growing hemp is currently banned because it is classified as an illegal drug by the Narcotics Act of 1979.

Varieties containing levels of tetrahydrocannabinol, or THC, lower than 0.3 per cent are allowed be grown.

The foundation is researching ways to breed a strain that complies with the law ahead of seeking permission for legal cultivation.

Maejo University, Chiang Mai University Medical Sciences Centre, the Highland Research and Development Institute, the foundation, Chulabhorn Research Institute and the Botanical Garden Organisation are working together to find a solution.

Maejo deputy dean Arkhom Kanchanaprachot heads the hemp project and said all local varieties of hemp would be collected and grown at seven foundation centres.

As well as acceptable THC levels the plants must produce strong fibre.

Botanical Garden Organisation director Veerasak na Nakhon said if hemp cultivation was supported by the government it could generate substantial income.