The Monetary Authority of Singapore (MAS) said it has issued prohibition orders (POs) against former remisier of Maybank Kim Eng Securities Kelvin Ang Wee Keng and former NRA Capital research head Lee Chee Waiy.

It has also served notice of its intention to issue a PO against former BSI Bank wealth planner Yeo Jiawei. The six-year PO against Ang and Mr Lee took effect from Oct 30, the MAS said.

Meanwhile, the authority has served notice of its intention to issue a permanent PO against Yeo, who has been investigated by the Commercial Affairs Department (CAD) on 1MDB-related matters.

Yeo was convicted by the State Courts in Singapore on several charges, including money laundering, cheating, and tampering with witnesses during CAD's investigation. The proposed PO will prohibit Yeo for life from providing any capital market and financial advisory services; and taking part in the management of, acting as a director of, or becoming a substantial shareholder of any capital market and financial advisory services firm in Singapore.

Ang was convicted of an offence under the Prevention of Corruption Act for bribing Mr Lee with $3,000 to expedite the preparation of a valuation report on PetroSaudi Oil Services Limited (PSOSL).

Mr Lee, the primary person in NRA Capital working on the valuation of PSOSL, accepted the bribe from Ang and applied inappropriate methodology and assumptions in the valuation of PSOSL.

The POs will prohibit them for a period of six years, from providing any capital market and/or financial advisory services; and taking part in the management of, acting as a director of, or becoming a substantial shareholder of any capital market and financial advisory services firm in Singapore.

To date, a total of six persons involved in 1MDB-related breaches have been issued POs by the MAS, with notices of intention to issue POs served on another two persons.

The POs issued have ranged from six years to lifetime bans.

"MAS expects professionals in the financial services industry to uphold high standards of integrity and proper conduct," said Mr Ong Chong Tee, MAS deputy managing director (financial supervision).

"Those who fall short of these standards will be dealt with firmly, to safeguard public trust in our financial institutions and Singapore's reputation as a clean financial centre."