If adopted, the recommendations will mean more people taking the drugs
The World Health Organization is changing its advice on HIV drugs, asking that they be given sooner and to breastfeeding mothers with the virus.
Experts say the advice is based on the most up-to-date information available and will cut infection rates and save lives.
But it will mean many more people needing treatment, which will cost more money and time.
An estimated 33.4 million people are living with HIV/Aids.
The World Health Organization (WHO) wants adults and adolescents to receive anti-retroviral therapy (ART) before their immune system strength falls below 350 cells per cubic millilitre of blood, regardless of whether they show symptoms.
It also wants the drug Stavudine, widely used in developing countries because of its low cost and widespread availability, to be phased out in favour of Zidovudine or Tenofovir, which do not have the same long-term and irreversible side effects.
And for the first time, the WHO is calling for breastfeeding mothers, or their babies, to be given the drugs to prevent transmission of the disease.
The International Development Minister, Mike Foster, said the guidelines would be supported though they would "significantly increase the demand for treatment".
"The Department for International Development is committed to increasing access to effective and affordable HIV treatments," he said.
"That is why UK aid supports the cheaper manufacturing of current treatments, and the Unitaid [the UN body on drugs for killer diseases] patent pool to help develop new, effective and affordable HIV treatments, particularly for children and for people living in developing countries."
Falling prices and increased testing have led to a marked rise in the number of people in the poorest parts of the world receiving treatment for HIV.
The number of people on anti-retrovirals had risen by a million by the end of 2008, a 36% increase from the previous year, the WHO said.
But despite the progress, less than half of those needing treatment, currently receive it.
The WHO estimates that since the availability of effective HIV drugs in 1996, some 2.9 million lives have been saved.