The director of UN AIDS, Eamonn Murphy, says Papua New Guinea needs to invest more and fix supply chain issues if it is to meet goals to curb HIV.
Mr Murphy said PNG in recent years had faltered in its response to HIV and Tuberculosis.
UN Aids said PNG has fallen behind the 90 -90 - 90 goal.
Under this plan, by 2020, 90 percent of people living with HIV would know their HIV status, 90 percent of people diagnosed with HIVwould be receiving sustained antiretroviral therapy and 90 percent of all people receiving this therapy would have the virus under control.
Mr Murphy said action needs to be taken or PNG faces a crisis.
"Tuberculosis is the greatest killer of people living with HIV, here in Papua New Guinea and elsewhere. And Papua New Guinea is both high burden for TB but even more so multi drug resistant TB. So, you put multi drug resistant TB with people who are resistant to HIV treatment and we have a real crisis."