He said New Zealand authorities were in contact with Australia but as yet had no information about the woman and did not know her name.
He said there was a question about whether the law should be expanded and that could be considered as part of the major review of security legislation currently underway.
However, he doubted New Zealand would go so far as to strip citizenship. It would be difficult to get enough support to pass such a measure. "Secondly it raises the issue of leaving people stateless, so I think it's unlikely. I just think that ultimate step of removing someone's citizenship is very unlikely."
It was likely the Terrorism Suppression Act would apply if such a person returned to New Zealand, the law which covers those involved in terrorist activities.
The foreign fighters legislation passed in New Zealand last year provided for matters such as passport confiscations for up to three years to stop people travelling overseas to fight for Islamic State and gave spy agencies greater powers to conduct surveillance without warrants on suspected terrorists.