In a joint statement, WHO and UNAIDS said research has long shown that anti-retroviral (ARV) medicines reduce AIDS-related deaths and prevent HIV transmission.
These benefits, however, are only likely to occur if individuals know their status and start treatment early.
"Early HIV diagnosis through different HIV testing approaches has become an important strategy for HIV prevention and control in the 21st century," said WHO Regional Director for Western Pacific Shin Young-soo.
"Moreover, people diagnosed with HIV should be linked to care and start treatment as early as possible to harness the benefits of antiretroviral treatment," he said.
Across the region, knowledge about HIV testing and counseling among key populations is low. Key populations are at higher risk for HIV, the statement said.
By Ruchi Singh