"This is a robust and mature relationship,"NZ Prime Minister Jacinda Ardern told reporters in an unprompted and strongly-worded statement at the start of her weekly press conference on Monday.

Questions about whether New Zealand's once-strong links with the world's second-largest economy had weaken after technology from Chinese tech giant Huawei was rejected from a 5G internet rollout by New Zealand's cyber security have caused headaches for Kiwi lawmakers in recent weeks.

Since the launch of a major China-New Zealand tourism scheme was delayed this month and an Air New Zealand plane turned around halfway to Shanghai, opposition politicians have been keen to play up what they say is a rift caused by sloppy diplomacy.

Adding to the woes, an article in the English version of China's People's Daily, often described as a government mouthpiece, described Chinese tourists cancelling their trips to the Shaky Islands after "New Zealand stabbed us in the back".

Some exporters, including seafood company Sanford, say they've seen hold-ups at Chinese ports.

Politicians and government agencies have been calling for calm.

New Zealand's Ministry for Primary Industries refuted claims products were facing delays while promotion group New Zealand Trade and Enterprise told politicians it could not confirm if there was a pattern or anything had changed.

On Monday, Ardern took the unusual step of making a statement to "correct some of the inaccuracies that I have heard".

"Our officials in China have confirmed that New Zealand primary products continue to clear the border as usual. There is no indication anything out of the ordinary," she told reporters in Wellington.

"In a trade relationship of this size .. .there will sometimes be temporary technical difficulties ... We need to keep these in context."

Ardern also pointed to increasing tourism numbers over 2018.

"New Zealand and China have differences of views on some issues, as we do with any other country," she said. "We manage these differences together in a mutually respectful way."

Beijing, meanwhile, also talked down suggestions it had warned its citizens against travelling to New Zealand.

"Those insisting on such an interpretation are evidently either making a big fuss over nothing or harbouring ulterior motives," a Foreign Ministry spokesperson, Geng Shuang, told media.

"We, not a Chinese newspaper, represent the official position of the Chinese government."

Ardern has yet to visit Beijing since being elected in 2017 and delays in a long-promised trip have raised suggestions of a snub, which she has rejected.

Australian Associated Press