Another director has quit the board of Singapore Post, adding to the string of resignations following a probe into the firm's corporate governance lapses.

Deputy chairman Goh Yeow Tin, 65, who had been put in charge of post-merger integration as well as business and operations in Singapore after former chief executive Wolfgang Baier's shock resignation last December, is resigning with effect from June 24, SingPost said in a market filing yesterday.

"I have decided to step down from the SingPost board as I wish to devote more time to my other commitments," said Mr Goh in response to queries from The Straits Times. He did not comment further.

Mr Goh, who sits on the board of 10 other companies including Sheng Siong Group and Vicom, joined SingPost as a director in July 2014.

Last month, during an audit into SingPost's failures to make accurate interested-party disclosures in relation to its acquisitions of two freight forwarders, former SingPost chairman Lim Ho Kee announced that he would quit the board in July. When the audit report was released earlier this month, former lead independent director Keith Tay, who was at the centre of the investigations, resigned from the board.

Mr Goh's resignation comes just days after SingPost's first board meeting under newly-appointed chairman Simon Israel. SingPost said in December that Mr Goh would be appointed an executive director for 12 months to aid in transition after Dr Baier's departure.

Mr Goh is leaving before that 12-month period is up, but post-merger integration activities are being led by a task force, said SingPost spokesman Peter Heng.

National University of Singapore business school associate professor Mak Yuen Teen said Mr Goh's departure was positive news.

"I think this allows the new chairman and the nominating committee a great opportunity to renew the board and improve the skills, experience, diversity and independence of the board," he said. "I expect more departures as the board size is adjusted downwards while (SingPost is) bringing in new directors."

Meanwhile, SingPost continues to search for a new CEO. The postal and e-commerce group is also due to release findings of an independent review into its corporate governance practices before its annual shareholder meeting in July, which it said will tackle some of the concerns not addressed by the recent audit into its disclosure lapses.

SingPost shares closed half a cent lower at $1.585 yesterday.