China's biggest security ally in the Pacific, the Solomon Islands is hosting the annual Pacific Islands Forum (PIF) of the 18-member bloc in September.
Three island states have diplomatic ties with Taiwan and not China, and they had expressed concern Taiwanese officials would be blocked from entering the country. Solomon Islands switched ties from Taiwan to China in 2019, and removed Taiwan from a list of countries eligible for concessional entry in April.
Beijing, which has deepened its ties in the Pacific, claims Taiwan as its territory.
Manele told the Solomon Islands parliament on Wednesday his cabinet had decided no dialogue partners would be invited to this year's event, because a review of each country's relationship with the Pacific had not been completed.
He said he had informed PIF's 18 leaders of the decision this week.
The World Bank, Asia Development Bank and civil society groups would attend, he added.
Opposition party politician Peter Kenilorea Jr, chairman of the parliament's foreign relations committee, said the decision was "a massive missed opportunity" for Pacific countries to meet global donors.
"We know this issue is all about China and Taiwan," he told parliament.
After leaders were told of the decision, Marshall Islands President Hilda Heine criticised interference in PIF's affairs in a speech to the Taiwan ally's parliament.
China had "interfered" at last year's meeting in Tonga to change the language of the leaders' communique, Heine said. References to Taiwan were removed after Chinese diplomats complained.
The Pacific Islands is among the world's most aid-reliant regions, and on the frontline of rising sea levels.
The region has also been a focus of increasing security competition between the United States and China.
While US allies Australia and New Zealand are the largest forum members, neither Beijing nor Washington are part of the group.
Kenilorea Jr said he feared that China, which has a strong presence in Solomon Islands, will hold bilateral meetings with Pacific leaders on the margins of the forum regardless.
"This could be seen by some PIF leaders as a betrayal of the collective and could risk an even bigger rift of the group," he said.
China's embassy did not respond to a request for comment.
PIF's foreign ministers will meet in Fiji next week.
