Tongan MPs have been asked to explain why they unanimously passed a constitutional amendment which some people warn could deny women a right to justice.
Clause 89A of the constitution, which requires judges to consider custom and tradition in their rulings, was passed without going to public consultation.
The move has been strongly criticised by the Tonga Law Society.
The director of the Women and Children Crisis Centre, Ofakilevuka Guttenbeil-Likiliki, says they are gravely concerned.
She said rape, sexual assault, domestic violence cases could be hijacked by so-called 'traditions and practices.'
"All the hard work we have been doing, lobbying for the Family Protection Act, we are currently lobbying for an amend ment to the rape laws under the definition of rape. We are lobbying for and advocating for harassment policies through the public service, and then to have something like this come out of the blu, I think it is really disappointing that parliament didn't take due diligence," Ms Guttenbeil Likiliki said.
She feared how this would impact on their work to stop sexual and domestic violence.
"How is this defined. Is the taking of pigs and traditional mats to apologise to the victims' families, is that going to be considered a traditional practice and value, and therefore undermine the woman's access to justice by reducing the penalties that the perpetrator could face in the sentencing?" she said.