Singapore's white collar-crime investigators have interviewed KTL Global executive chairman Tan Tock Han as part of an ongoing probe into possible offences under the Singapore Penal Code, the company said yesterday.

The offshore services company said that its other directors have also received requests from the Commercial Affairs Department (CAD) for interviews. KTL Global added that its directors or management staff may be required to attend further interviews to assist in the investigations.

"The company has extended and will continue to extend its fullest cooperation to the CAD in its investigations," KTL Global said in a statement.

In October last year, KTL Global said the CAD and the Monetary Authority of Singapore (MAS) had requested the assistance of its then chief executive officer Tan Kheng Yeow in an investigation concerning a possible offence under the Securities and Futures Act.

Mr Tan subsequently surrendered his passport to the authorities and resigned as CEO.

In December that year, the MAS requested access to information, including details of all local and overseas bank accounts held by the company and all accounting documents and books from Aug 1, 2014, to Dec 31, 2015.

Last month, the CAD sought further documents and information from KTL Global, and also interviewed chief financial officer Ng Kok Peng.