The United States on Thursday threw its support behind World Bank chief Jim Yong Kim for a second term at the helm  of the multilateral development lender.

"I am proud to announce that today the United States has nominated World Bank President Jim Kim for a second term," said US Treasury Secretary Jacob Lew in a statement.

"President Kim has used his first term to focus the World Bank on effectively addressing today's most pressing global development challenges in innovative ways, from ending extreme poverty and tackling inequality, to combating climate change," Lew said.

The Treasury secretary also praised Kim's leadership of the 189-nation institution in responding to major crises, including battling the Ebola pandemic and addressing the refugee crisis.

He highlighted Kim's sponsorship of "needed reforms" at the World Bank, created in 1944 along with sibling institution the International Monetary Fund.

"Re-electing President Kim will allow the World Bank to continue to build on these important initiatives and reforms," Lew said.

Kim, 56, a US physician, indicated Tuesday that he would seek a second five-year term. His first term ends on June 30, 2017.

That coincided with the Bank's announcement of the start of the selection process for the presidency on Thursday. After the close of the nominating period on September 14, the board will publish a short list of up to three candidates.

Consideration of the contenders will take between two and three weeks.

Following an unwritten rule, the United States, the Bank's largest shareholder, has always chosen its president, while the IMF leader has been drawn from Europe.

In 2012, Kim was the first American candidate to face competition when Nigerian Finance Minister Ngozi Okonjo-Iweala also contended for the presidency.

After taking office in July that year, Kim announced a new goal of eradicating extreme poverty by 2030 and a sweeping internal reorganization to foster collaboration across the Bank.

Earlier in August, the World Bank staff association said in an open letter that the tradition of the US picking the president flew in the face of  principles of transparency, diversity and merit-based selection.

Kim's reforms appear to have alienated many staff members, who in employee surveys have reported feeling detached from senior management and unsure of the direction of policy. (AFP)