A New Zealand court has ruled that a man who did not tell his sex partner that he was HIV-positive should not be prosecuted, because he used a condom.
In what is believed to be a legal first, Justin Dalley, 36, was acquitted of two charges of criminal nuisance.
New Zealand law says people with HIV should disclose their condition if it could endanger their partner.
The New Zealand Aids Foundation welcomed the ruling, saying it highlighted condoms kept people safe.
Judge Susan Thomas said that the defendant had done his legal duty by taking reasonable precautions.
"The evidence of health experts in the area is that the use of a condom for vaginal intercourse is sufficient for the prevention of the transmission of HIV and that this can be met without the requirement for disclosure," she said.
Mr Dalley's lawyer, Donald Stevens, welcomed the finding, which he said set an important legal precedent, not only for New Zealand, but for Australia, North America and Britain.
There have been concerns that the law could discourage those who may be HIV-positive from getting tested for the condition.
Rachael Le Mesurier, executive director of the New Zealand Aids Foundation, said the ruling emphasised the importance of safe sex.
"Relying on HIV-positive people to tell you, and assuming that unprotected intercourse is safe if HIV is not mentioned, is a much riskier strategy, especially as approximately one third of people with HIV in New Zealand don't know they have it," she said.