WELLINGTON/SYDNEY (Reuters) - An undiplomatic dispute between China and the island of Nauru, which is an ally of China’s rival Taiwan, has marred the opening of a Pacific Islands Forum, highlighting China’s growing reach in the region.

Nauru is hosting leaders of 18 Pacific nations, plus delegations from non-member countries including the United States and China, at a time of growing tension and rivalry in a strategically important region with access to swathes of resource-rich ocean.

But Nauru President Baron Waqa criticized China’s envoy to the forum as “very insolent” and a “bully” for speaking out of turn after an angry exchange at the opening of the annual gathering.

“The Chinese demanded to be heard when (Tuvalu’s) prime minister was about to speak,” Waqa told a news conference late on Tuesday, after media reported a heated start to the closed-door meeting.

“He insisted and was very insolent about it, and created a big fuss and held up the meeting of leaders for a good number of minutes when he was only an official. So maybe because he was from a big country he wanted to bully us,” Waqa said.

A video of part of the incident, posted on Facebook by Fijian magazine Islands Business, showed China’s delegate demanding that he be heard, citing his seniority.

Nauru and Tuvalu are two of six Pacific countries to have diplomatic ties with Taiwan, which is a major source of tension with China, which regards Taiwan as a wayward province, to be taken back by force if necessary.

Speaking in Beijing, Chinese foreign ministry spokeswoman Hula Chunying said it was Nauru that engaged in poor and undiplomatic behavior.

“Nauru, as the host of the forum, violated international norms and the rules of the forum, and put on a clumsy farce,” Hula told a daily news briefing.

Nauru originally demanded the Chinese delegates enter using normal passports but after protests and threats of a boycott by most other participants, they were allowed in on diplomatic passports, she added.

‘DISSATISFACTION’

During the meeting, Nauru obstructed China’s delegation from speaking, so they lodged “stern representations” and walked out of the venue in protest, Hula said.

“Many countries representatives at the meeting also left the meeting venue and expressed strong dissatisfaction with the Nauru side.”

China’s delegation was led by Du Qiwen, its ambassador to Fiji.

Waqa said protocol dictated speaking priority was given to ministers over diplomats.

China has become one of the dominant economic players in the Pacific, spending billions of dollars in trade, investment, aid and tourism in a region that staunch U.S. ally Australia has long regarded as its “back yard”.

Chinese lending to the region has surged from nearly zero to $1.3 billion over the last decade, stoking concern that tiny nations could end up overburdened and in debt.

It is also the second-largest bilateral donor in the region, behind Australia. Nauru has no diplomatic relations with China.

New Zealand Foreign Minister Winston Peters, who appears the in the video posted on Facebook suggesting as a compromise that China’s delegates could speak after Pacific ministers, told reporters on Tuesday there was no walk-out by China’s delegation.

The dispute echoes an incident in 2017 when Chinese delegates were reported to have disrupted the opening remarks at a conference in Australia about conflict diamonds, because a Taiwan delegation was invited.