The protest comes against a backdrop of reasonably stable ties in recent years, with New Zealand Prime Minister Christopher Luxon having visited China this year.

The embassy cited “harassment and interrogation without cause” by New Zealand security and intelligence agency official in the case of a transiting citizen, adding that some of the confiscated digital devices were not returned.

“The embassy of China in New Zealand has lodged a serious representation with the New Zealand ministry of foreign affairs and trade and deplores the unwarranted conduct and harassment,” it said in a statement on its website on Tuesday.

In response, a New Zealand foreign ministry spokesman said the embassy had been advised that all those transiting or entering the country must obey its laws and regulations, including those concerning national and border security.

“These laws and regulations are applied in a non-discriminatory manner, regardless of country of origin,” the spokesman said in a statement that did not refer to details of specific cases.