HIV/Aids is having a crippling effect on the workforce of many countries, a report by the International Labour Organization for World Aids Day says.
Rallies are taking place in many countries to mark World Aids Day
The ILO said HIV/Aids killed almost 3.5 million people of working age in 2005.
South Africa, among the worst-affected nations, has announced a plan aiming to halve the infection rate by 2011 and to boost the use of antiretrovirals.
In a speech to mark World Aids Day, UN Secretary General Kofi Annan urged more frank and open discussion of HIV/Aids.
All politicians had to consider themselves personally accountable for stopping the spread of the disease, Mr Annan said, as did every individual.
"It requires every one of us to help bring Aids out of the shadows and spread the message that silence is death," he said.
South Africa's government has in the past been accused of not doing enough to fight the HIV/Aids pandemic.
More than five million South Africans are infected with the virus.
HIV/Aids is costing 1.3m jobs a year, many in sub-Saharan Africa
The announcement by Deputy-President Phumzile Mlambo-Ngcuka of a five-year action plan was expected to mark a significant change in policy.
However, the BBC's Southern Africa correspondent Peter Biles says Friday's launch was downgraded from a fully-fledged plan to a framework document.
Many details of the new policy have still to be spelt out, he says.
South Africa's former policy, which emphasised diet over the use of antiretroviral (ARV) treatment, was widely criticised.
The health minister responsible, Manto Tshabalala-Msimang, is reported currently to be on sick leave and has played little part in recent developments, our correspondent adds.
Figures recently released by the UN reveal that in terms of numbers, India is now facing the most severe HIV/Aids burden of any country in the world, with 5.7 million people infected.
Former US President Bill Clinton said in a BBC interview that India was the new epicentre of global infection.
He described the challenge to control the spread of the virus in India as "breathtaking".
Elsewhere, countries are marking World Aids Day with a series of events, including:
- The broadcast of radio and television messages in 25 countries across Africa aimed at preventing the spread of the disease among young people
- A march by Indonesian activists through the streets of the capital, Jakarta, demanding an end to the stigma attached to HIV/Aids
- A plan by activists in Thailand to create the world's "longest condom chain", a ribbon of 25,000 condoms stretching through a Bangkok park
- An announcement by Australian Foreign Minister Alexander Downer for an extra US$170m (£83m) to help its Asia-Pacific neighbours tackle the HIV/Aids epidemic
In its report, the ILO calls for sustained action worldwide to improve access to AVR treatments to cut mortality rates.
Without this, it estimates that the cumulative loss to the global workforce from the virus could rise to 45 million by 2010 and almost double again by 2020.
ILO estimates that more than 36 million people of working age are now living with the virus, the vast majority in sub-Saharan Africa.
This has had a damaging effect on the availability of labour in the worst-affected countries and has stunted economic growth.
The ILO conducted research into the impact of the virus on 43 countries with some of the highest rates of infection in the world.
More than 70% of these countries were in sub-Saharan Africa.
Based on its findings, it has estimated that 1.3 million new jobs have been lost every year between 1992 and 2004 because of the virus.
This, in turn, reduced annual economic growth by an average of 0.5% over the period and 0.7% for sub-Saharan countries.
"HIV/Aids is adding an enormous burden to countries struggling to emerge from poverty," said Odile Frank, one of the report's authors.
"We need more employment opportunities for people with HIV/Aids and an end to discrimination against people with the virus to help them to secure work."
More than two million children around the world are now living with Aids while those aged 15-24 account for half of new infections.
The ILO said many children were forced to seek employment because they were living in extreme poverty, while their parents had either died from Aids or were too sick to work.
Other children found themselves working in unregulated industries such as the sex trade which exposed them to being infected.
The ILO said increased access to ARV treatments could significantly reduce the impact on the global workforce.
"The prospect of averting between one-fifth and one-quarter of potential new losses to the labour force should serve as a powerful incentive to target the workplace as a major entry point to achieve universal access to ARVs," the report concluded.