KUALA LUMPUR • Malaysian banker Nazir Razak said he wished he had not passed on funds from the account of his brother, Malaysian Prime Minister Najib Razak, to Umno politicians ahead of the 2013 general election.

The Wall Street Journal (WSJ) reported on Thursday that Datuk Seri Nazir received US$7 million (S$9.4 million) transferred into his account from his older brother's, and the money was then disbursed to party politicians ahead of the polls.

In a posting on Instagram late on Thursday, Mr Nazir clarified that he had been asked by Datuk Seri Najib "to urgently help pass on cash to party machinery", and that he "assumed and believed, in good faith, that the funds came from legit political fund-raising".

The youngest brother of PM Najib said that he understood the furore over the revelations and "in hindsight" wished he hadn't done it. He assured netizens that not a cent of the money was retained by him.

Mr Nazir has been critical of the state of Malaysia's institutions and politics, and has slammed sovereign wealth fund 1Malaysia Development Berhad (1MDB) and called for its board to resign. Thus, his involvement in the disbursement of political funds has drawn surprise.

Earlier, the WSJ said that Mr Nazir, who was chief executive of CIMB at the time, confirmed in a statement that the money was distributed in accordance with instructions from party leaders.

He also said he believed the money was from donations he helped to raise from Malaysian companies and individuals for the election.

"I had no knowledge whatsoever that these funds may have originated from any other source," he said in the statement. "The entire amount was paid out in cash to various recipients according to the instructions of the party president, and the account was closed with a zero balance."