Australian researchers say oestrogen can be used to create a "living condom" to protect uncircumcised men from Aids.[Agencies]

Australian researchers say they have unlocked the key to blocking HIV infection in men in a breakthrough which could arrest the global Aids epidemic.

The ground-breaking study uses the female hormone, oestrogen, to create a "living condom" in men, shielding them from the virus.

The development is being touted as a critical step in reducing sexually transmitted HIV, particularly in uncircumcised men, who are more at risk of infection.

University of Melbourne researchers Dr Andrew Pask and Professor Roger Short said their discovery had the potential to cut the spread of HIV in half.

And the research underpinning their work could spark calls for a revival of circumcision.

Dr Pask and Prof Short have discovered that by applying oestrogen to the vulnerable inner foreskin they can boost the body's natural defences against HIV.