The company secretary of troubled industrial waste gas treatment company China Environment has resigned.

Mr Ho Soo Hui, who was responsible for group corporate secretarial matters, stepped down from his post on Monday.

China Environment said in a Singapore Exchange filing yesterday that the 48-year-old had been appointed to the role in October last year. No reason was cited for his resignation.

Mr Ho's departure follows a series of developments around China Environment. Just last week, the firm said it had received a letter of demand from Ms Chen Fen Hua, the wife of former executive chairman Huang Min, seeking 47.1 million yuan (S$9.6 million).

The letter is claiming the amount for Fujian Mintai Environmental Protection, a company for which Ms Chen is the legal representative. The deadline for payment stipulated in the letter is today.

China Environment said then that it was assessing the basis and merits of the claims and would take appropriate action, and that it had reported Mr Huang to the Commercial Affairs Department, Singapore's white-collar crime investigation unit.

The company had said back in February that it would report allegations of fraud regarding Mr Huang to the authorities in China.

Last month, a unit of China Environment, Fujian Dongyuan Environmental Protection (FJDY), was reported to have lost a civil suit brought by Zhongxin Bank in China.

FJDY is liable for a loan of 36.67 million yuan and loan interest of 563,870 yuan. This was due within 10 days of the effective date of judgment, together with punitive interest of about 9.5 per cent annually from Dec 19 last year, up to the full settlement date.