The knowledge of his partners of his HIV status at the time of having sexual relations with him will be key, according to criminal law specialist Professor Chris Gallavin.
He described New Zealand law in this area as being "in a state of flux".
"Every now and then we hear of similar cases here where the obligations of those with HIV to disclose their status to sexual partners is brought to the fore," he said.
"Much the same as many other countries, New Zealand law has struggled to know just how to deal with people who fail to disclose to their partners that they are HIV positive - the law really is a mess in this area."
There is no provision of the Crimes Act that is a "neat fit" for such cases, said Prof Gallavin, Deputy Pro Vice-Chancellor for the College of Humanities and Social Sciences at Massey University.
In the past, perpetrators have been charged with anything from poisoning to nuisance to assault.
"But we now appear to have case law authority that says a failure to disclose status as HIV positive could result in a conviction of rape," he said.
"As a result of case law, it now appears that in New Zealand if a person subsequently finds out that a person they had sex with knowingly had HIV and failed to disclose it, then a complaint to the police could result in the person being charged with and convicted of rape.
"The circumstance is horrific and I feel for the victims of such an act, but it is not right that they be convicted of rape.
"Such a conclusion is an ill fit, just as it is in the case of poisoning. The question of what exactly the wrong is, and how the law should deal with it, is very difficult indeed.
"For example, what is the obligation of all of us to ask the question of our partners or use protection? How much liability do we all take upon ourselves when we enter into risky behaviour knowing full well that contracting a disease might well be the consequence?
"Undoubtedly, that obligation might not exist when one is having sexual relations with a life-long partner in a monogamous relationship, but in the context of a one night stand it might be very high. What is clear is that anyone with a communicable disease of any type should inform their sexual partners, both as a matter of respect for the other person and in some cases as a matter of law."
He adds: "It is only right, and in some cases a legal necessity, for the other person to have all the facts before them that are important to their decision of whether to have sex.
"If you mislead someone or remain silent over something that they should know then you might not only have your own disease to contend with but also the police."
