Jacinda Ardern reveals NZ concerns with China over its use of fake image in feud with Oz

Prime Minister Jacinda Ardern says the Government has raised concerns over China's use on social media of a doctored image of an Australian soldier holding a knife to a child's throat.

Although Ardern stopped short of what could be considered a strong rebuke, she said it was a concerning development from China.

"New Zealand has registered directly with Chinese authorities our concern over the use of that image ... in the manner that New Zealand does when we have such concerns," she told media this morning.

"An image has been used that is not a genuine image."

A Chinese Foreign Ministry spokesman, Zhao Lijian, shared the image on Twitter yesterday and has since caused a diplomatic stoush between Beijing and Canberra.

Australian Prime Minister Scott Morrison reacted swiftly and unequivocally to the image being shared on social media, calling it "truly repugnant", and called for an apology from the Chinese government.

"The Chinese government should be totally ashamed of this post. It diminishes them in the world's eyes."

But neither Ardern, nor her Foreign Affairs Minister Nanaia Mahuta, were prepared to go as far as Morrison with their comments this morning.

"New Zealand doesn't support disinformation that has the potential to be inflammatory and cause further comment," Mahuta said.

She wouldn't say what the Government's message to China was and, when pressed, she only repeated the comments about not supporting disinformation.

Asked if she had spoken to the Chinese ambassador about this, she said: "Not as yet."

But Ardern has confirmed the Government had registered its concern directly with Chinese officials.

"That, for us, is a principled position that New Zealand takes regardless of who that exchange is happening between."

National Party leader Judith Collins said she hadn't seen the Twitter image, but it sounded "abhorrent" and it was right for New Zealand to raise concerns with China.

She said New Zealand was a trading nation, so it was always a "difficult" diplomatic line to walk between China and Australia.

The offensive image is in reference to a report which alleged elite Australian soldiers had carried out war crimes including the killings of 39 Afghans in a series of incidents that are being referred for special investigation and potential prosecution.