The World Health Organisation (WHO) issued new advice on the treatment of HIV on Monday, the eve of World AIDS day, saying drugs should be given earlier and even be prescribed to breastfeeding mothers.

The WHO says adults and adolescents should receive anti-retroviral therapy (ART) when their immune system strength falls below 350 cells per cubic millimetre of blood. In 2006, the organisation had set the level at 200 cells per cubic millimetre.

"These new recommendations are based on the most up to date available data," said Hiroki Nakatani, assistant director general for HIV/AIDS, TB, Malaria and Neglected Tropical Diseases at the World Health Organization.

"Their widespread adoption will enable many more people in high-burden areas to live longer and healthier lives."

The WHO also recommended pregnant women exposed to the virus could be treated with anti-retroviral drugs (ARVs) from the 14th week of pregnancy and that treatment could continue during breastfeeding.

"Several clinical trials have shown the efficacy of ARVs in preventing transmission to the infant while breastfeeding," a WHO statement said.

The WHO also said Stavudine, a relatively cheap HIV/AIDS drug that is widely used in developing countries, should be replaced with Zidovudine and Tenofovir as they have less harmful side effects.

Some 33.4 million people worldwide are living with HIV/AIDS and there are 2.7 million new cases each year.