China's growing hold over Pacific nation Solomon Islands is "alarming," a powerful opposition figurehead told AFP Monday ahead of elections that could further entrench Beijing's foothold in the region.

Solomon Islands has warmly embraced China under mercurial Prime Minister Manasseh Sogavare, with the two nations inking a murky security pact in 2022.

A torrent of Chinese aid and investment has flowed into the country during Sogavare's five years at the helm, and the 69-year-old has vowed to further deepen these ties if re-elected on Wednesday.