The International Monetary Fund is set to agree to grant up-and-coming developing nations greater power in running the fund, The Wall Street Journal reported on Thursday.

At an IMF board meeting due late on Thursday, member governments are expected to sign off a plan to quickly increase the voting shares of China, Turkey, Mexico and South Korea, allowing them more say in which countries get IMF loans and what economic measures they must adopt in order to qualify for them, according to the report.

"It will improve the legitimacy and relevance and credibility of the IMF -- that's what we have to restore," said South Korea's Jong Nam Oh, who represents 14 countries on the IMF board.

Current "shares don't reflect the real weight of the members in the world economy," he added.

The IMF action would make the plan all but final, with formal ratification expected at the global lender's annual meeting in Singapore next month, said the report.

The decision "locks in the contours of what an agreement will be," Timothy Adams, U.S. Treasury undersecretary for international affairs, was quoted as saying.

While South Korea's economy is twice the size of Belgium's, Seoul's voting share in the IMF is only about a third of that allotted to Brussels, according to Treasury figures.

Over the past year, U.S. Treasury officials, along with IMF Managing Director Rodrigo de Rato, have intensified their push for a new approach to voting shares, said the report.