China has become one of the largest bilateral infrastructure lenders to the Philippines, but its finance commitments swing wildly with the two countries' fickle political relationship, a new report said, warning that lenders could shift focus as Beijing and Manila spar in the South China Sea.

China committed a total of $9.1bn in state-directed finance to the Philippines between 2000 and 2022, according to an investigation published on Wednesday by AidData, a research lab at William & Mary university.