The four MPs hail from across the political spectrum and visited Taiwan as part of a cross-party delegation in May, national broadcaster RNZ reported.

Foreign Minister Winston Peters' office confirmed the ban and said he was "surprised" by the move.

The top diplomat has asked New Zealand diplomats to raise the issue with Chinese officials in Beijing and Wellington.

China claims self-ruled Taiwan is part of its territory and opposes the self-governed island's participation in international organisations and exchanges with other countries.

Peters' office insisted on Thursday that the visit by the MPs was not inconsistent with New Zealand's "One China" policy, in which Wellington recognises Beijing's claim over Taiwan.

"New Zealand Members of Parliament are free to make their own individual decisions, independent of the government, about how they respond to invitations to travel overseas," his spokesperson said.

While Wellington does not have diplomatic relations with Taiwan, "this does not preclude New Zealand from maintaining trade, economic, cultural and indigenous exchanges", the country's foreign ministry said.

"We intend to continue these exchanges as they benefit the people of New Zealand and are entirely consistent with our One China policy."

One of the MPs slapped with a ban, Laura McClure, told RNZ that China was trying to intimidate New Zealand lawmakers.

"New Zealand is sovereign, and members of parliament have the right to represent the communities and constituents that we do, and we have the right to travel freely around the globe," she said.

"That is part of living in a free democracy."

The Chinese embassy in Wellington did not respond to a request for comment from AFP.

RNZ reported the mission has said it would reverse the ban if the politicians apologised.

"It's not exactly clear what we would be apologising for, and if it is just for travelling to Taiwan, I personally will not be apologising," McClure said.