The NT government has called for the UN to enforce compulsory and ongoing screening of all personnel in East Timor after a Darwin woman contracted the virus from a UN employee on leave.

Australia's peak HIV/AIDS body argued such infections may become more prevalent if mandatory testing were enforced.

"Screening people for HIV based on mandatory testing is not an effective means of preventing HIV infection and furthermore, can lead to stigma and discrimination," AFAO acting executive director Chris Ward said.

"The action that the NT government is demanding may unintentionally lead to effects such as reducing the likelihood that people would voluntarily seek HIV testing and therefore their willingness to access the appropriate information."

The UN Transitional Administration in East Timor (UNTAET) dismissed the government's demands as discriminatory and illegal in most countries.

But NT Chief Minister Denis Burke said highest priority had to be preventing a Cambodia-scale AIDS epidemic in East Timor.

"And more than that, I'm concerned about the spread amongst the heterosexual population of the NT," Mr Burke said.

"I find it amazing that all of a sudden something is discrimination against an individual when no-one seems to give a great deal of concern about the potential for infection amongst the (East Timor) population.

"If the UN wants to take a leadership role on dealing with the spread of AIDS ... I would have thought that it was a protective and necessary measure to ensure that any foreign workers were screened initially to ensure they were free of such a disease."