Prime Minister Jacinda Ardern says her party remains undecided on whether it will support or deny the Act party's motion to vote on if the abuse of the Uyghur minority in China amounts to genocide.
Act last week filed notice of a motion that would ask MPs to vote on whether human rights abuses in the Chinese region of Xinjiang amounted to genocide, calling on the Government to fulfill its obligations under international law.
The motion, filed by deputy leader and foreign affairs spokesperson Brooke van Velden, needs the support of each MP in the House in order to be debated.
The 1948 United Nations genocide convention defines genocide as acts "committed with intent to destroy, in whole or in part, a national, ethical, racial or religious group", which can take place in times of war or peace.
Several countries, including Britain, United States, Canada and the Netherlands, have accused China of committing genocide.
China denies such allegations, saying it has been combating separatism and Islamist militancy in the region.
On Monday, Ardern said a party position on the motion would be debated within caucus on Tuesday.
She said Foreign Minister Nanaia Mahuta had been "working generally" on the issue.
While declining to voice her personal opinion, Ardern said there were a set of legal definitions around use of the word genocide.
New Zealand had used the term officially on just three occasions - with Nazi Germany, Rwanda and Cambodia.
To meet the test required "verifiable information", she said.
"That is one of the reasons why we have repeatedly called for unfettered access ... in order to assess potential human rights abuses for the Uyghur.
"That is not to say there is not credible evidence of human rights abuses already, there is, but it is one of the things that we usually see preceding that definition."
Her comments followed a speech to the China Business Summit in the morning, when Ardern said the differences between China and New Zealand "are becoming harder to reconcile with", stating her "grave concern" for the Uyghur people.
Meanwhile the Green Party, which has long been raising concerns about the situation in China, will also decide its position on the motion at its Tuesday caucus.
Foreign affairs spokeswoman Golriz Ghahraman said more than just debating whether or not it was a genocide, New Zealand needed to do more to raise it as an issue internationally.
"We've seen Western countries label it a genocide and not take any more action."
Ghahraman said actions they'd like to see immediately included the Ministry of Foreign Affairs confirming if any New Zealand trade was occurring in areas of Xinjiang where slave labour was happening.
"Our focus will be on having New Zealand stand in solidarity with victims rather than giving it a label and moving on."
Van Velden said she felt parliamentarians had a duty to stand up for human rights, especially for those who "don't have a voice".
She said she thought it was clear the "atrocities" occurring amounted to genocide, and was concerned United Nations (UN) investigators were not being allowed in.
She hoped the discussion would lead to further action, but wouldn't pre-empt what that would look like.
"All I am looking for at this stage is to see if Parliament has the courage to stand up and debate the issue of genocide in China, and until we can I don't think we can go much further in discussing what to do."
Waikato University law professor Alexander Gillespie said while it was a good move to discuss the issue, he did not think politicians getting involved at this stage was the right way to address the situation.
It had risks for the Government politically both ways also, with a declaration likely to heavily impact dealings with China and invoke trade retaliation.
Meanwhile, a Labour block vote against it could be a "bad look" unless they have some alternative option.
"At a time of New Zealand is being accused of being too cuddly to China, it would look terrible.
"What you want is the UN experts to make such a determination - not politicians.
"Apart from the experts having much more credibility in the process, it also would depoliticise it."
If the UN experts continued to be denied, over a period of another six months of so, Gillespie said it could then be time for countries to make their own determinations.
A declaration could also invoke trade retaliation from China, he said.
"Even Australia which has received a lot of trade problems from China has not walked into this space. If we went first, expect payback."
A "midway point" would be to avoid a vote, but double down on the demands for UN expert access, and set a time limit.
Another option was offering a New Zealand-led team of independent experts to try to get to the bottom of it, he said.
The motion is no certainty yet, as if a single MP objects, it will be defeated.
Van Velden said she would be seeking support from the Business Committee on Tuesday for it to placed up the order paper to be raised in the House on Wednesday.
She'd also sent it to each political party to discuss at caucus to garner support.
If all MPs agree to it being debated, each party will have the opportunity to speak, and the Speaker of the House will ask whether they support the motion.
If a majority vote in favour, the motion would become the position of the Parliament.