An employee walks outside the World Bank headquarters in Washington, United States.

The World Bank's shareholders on Saturday endorsed a $13 billion paid-in capital increase that will boost China's shareholding but bring lending reforms that will raise borrowing costs for higher-middle-income countries, including China.

The multilateral lender said the plan would allow it to lift the group's overall lending to nearly $80 billion in fiscal 2019 from about $59 billion last year and to an average of about $100 billion annually through 2030.

"We have more than doubled the capacity of the World Bank Group," the institution's president, Jim Yong Kim, told reporters during the International Monetary Fund and World Bank spring meetings in Washington.

"It's a huge vote of confidence, but the expectations are enormous."

The hard-fought capital hike, initially resisted by the Trump administration, will add $7.5 billion paid-in capital for the World Bank's main concessional lending arm, the International Bank for Reconstruction and Development.

Its commercial-terms lender, the International Finance Corp, will get $5.5 billion paid-in capital, and IBRD also will get a $52.6 billion increase in callable capital.