The Solomon Islands opposition leader, Fred Fono, says the foreign minister's visit to Taiwan has been urgent.
The minister, Patteson Oti, is leading a four-member delegation to Taipei at the invitation of the Taiwanese government to discuss bilateral relations.
The foreign minister is a member of the National Party which had said it might switch the country's relations from Taiwan to China, but he had to reaffirm his support for Taiwan.
Mr Fono says the government had to visit Taiwan to show its loyalty.
"They need to rebuild back the image. They are part of a grouping that was opting to switch allegiance of diplomatic ties from Taiwan to China. So they need to rebuild back that image and visit Taiwan and reconfirm the commitment to the Republic of China government."
Mr Fono says his party supports the government's diplomatic links with Taiwan.
But the National Party leader and former prime minister, Francis Billy Hilly, and a former minister, Alfred Sasako, have said ties should be sought with China.