The travel restrictions were communicated through China’s embassy in Wellington and conveyed to the lawmakers by New Zealand’s Parliamentary Service, according to messages seen by The Associated Press on Thursday. The ban applies to lawmakers Laura McClure, Duncan Webb, Maureen Pugh and David Wilson.

China’s Foreign Ministry confirmed the sanctions on Thursday. Spokesperson Mao Ning said Beijing opposed visits to Taiwan by members of legislatures from countries that maintain diplomatic relations with China and urged those involved to respect China’s sovereignty and territorial integrity.

“Anyone who crosses the red line on the Taiwan question must pay the price,” Mao told a regular press briefing in Beijing.

According to communications relayed by parliamentary officials, the restrictions could be lifted if the lawmakers apologized for their visit to Taiwan. Two of the lawmakers publicly rejected that demand.

ACT Party lawmaker Laura McClure described the request as inappropriate and said she would not apologize. Labour Party lawmaker Duncan Webb said New Zealand lawmakers were entitled to engage with international partners and that he was prepared to accept the consequences of the ban.

New Zealand Foreign Minister Winston Peters’ office said visits by parliamentarians to Taiwan had occurred for decades and were not inconsistent with New Zealand’s One China policy, under which Wellington acknowledges Beijing’s position that Taiwan is part of China while maintaining unofficial relations with Taipei.

The government said officials in Wellington and Beijing would seek further clarification from Chinese authorities and formally express concern over the decision.

The sanctions mark the first known instance of New Zealand parliamentarians being barred from entering China over contact with Taiwan, according to the New Zealand government. Beijing has previously imposed similar restrictions on lawmakers from other countries as it intensifies efforts to discourage official engagement with Taiwan.

The issue has also drawn attention in neighboring Australia. Australian Foreign Minister Penny Wong said Canberra would raise concerns with Chinese officials and reiterated that lawmakers should be free to make independent decisions regarding overseas travel.

China regards democratically governed Taiwan as part of its territory and opposes official exchanges between Taipei and foreign governments or legislators. Taiwan rejects Beijing’s sovereignty claims and maintains its own elected government and foreign engagements.

The dispute emerges despite generally stable relations between New Zealand and China in recent years. China remains New Zealand’s largest trading partner and was the first Western nation to conclude a free trade agreement with Beijing.