BANGKOK - Thailand paved the way Monday for the sale of generic versions of two drugs, one to treat HIV/AIDS and the other for heart disease, effectively breaking their patents, officials said.

The government's decision to allow for either the production or purchase of generic versions of the drugs was applauded by aid agencies and activists, who said it would improve the lives of thousands of people, and set an example to other countries facing similar problems.

Public Health Minister Mongkol Na Songkhla said the decision was justified under international trade rules because the drugs' high cost constituted a crisis for the country's health sector.

According to the World Trade Organization's agreements on intellectual property, a government may issue a compulsory license in case of a national public health emergency. Such action has been taken by several countries, most notably Brazil and India, especially in the case of HIV medicines.

The drug to treat HIV is Kaletra, produced by U.S. health care company Abbott Laboratories. Plavix, a blood thinner, is sold by France's Sanofi-Aventis SA and Bristol-Myers Squibb Co, also from the U.S.

Sanofi-Aventis, which sells the blood thinner Plavix in Thailand, didn't have an immediate comment. Abbott said in a statement that it viewed the Thai government's actions as illegal and not in the best interest of patients.

Mongkol said generic production of Plavix would reduce the cost from about 70 baht ($2.06) a pill to less than six baht (18 cents).

He said the ministry was willing to talk to the companies about importing their drugs at cheaper prices.

"We ask for the understanding of pharmaceutical companies. Much of our affected population cannot afford your drugs and we want people to have access to the medicines that they need," Mongkol said. "We are willing to negotiate with the companies if they are willing to give some discounts for the import of their originals."

Thai officials last week announced their intention to declare compulsory licensing for the two drugs, drawing criticism from the industry's Pharmaceutical Research & Manufacturers Association, who said it could force more companies to relinquish their patents.

The association's president, Teera Chakajnarodom, said the decision also could have a wider impact on foreign investors. "They are concerned about continuing to invest in a country where the government cannot provide a basic guarantee for the safety of their assets."

Kannikar Kijtiwatchakul, a campaigner in Thailand for Medecins Sans Frontieres, or Doctors without Border, welcomed the government's move.

"It is a brave decision, despite both anticipated pressure from industry and possible threats to withdraw investments. The authorities have engaged in dialogue with companies before, but the discounts have been marginal. The licenxes will benefit a lot of people and will set an example to other countries who face the same problem."

More than 500,000 people in Thailand are living with HIV, according to UNAIDS, the UN agency that co-ordinates the global fight against the deadly virus.

The Thai government has a budget of 3.8 billion baht ($112 million) allocated to the treatment of HIV patients, Mongkol said, meaning it could afford only to provide medicine to 108,000 patients at the companies' price.

Around 200,000 patients in Thailand who suffer from heart conditions have blood clotting problems that could be treated with Plavix, but only 20 per cent of them have access to the medicine, he said.