Papua New Guinea's former country co-ordinator for the United Nations' joint programme on HIV/AIDS says young people must do more to help stop the virus from spreading.
Tim Rwabuhemba says official figures derived from antenatal testing indicate 60-thousand people.
Data from Human Rights Watch putting that number at more than 140-thousand.
Mr Rwabuhemba, who's just moved from his PNG role to its equivalent in Fiji, says more accurate figures won't be available until a new survey that includes men is launched, which he hopes will be sometime next year.
He says there's a lot of denial among young people.
"The young people themselves have not realised that really they are the source of target as far as HIV is concerned and for that matter there is a need for them to play a much more proactive role. So you'll find that the responsibility is left to other groups like churches as what I've been been talking about or private sector or poeple living with HIV. Somehow they have not realised that there's a need for them to really come together and address the epidemic as it affects them."