The chief executive's decision to rely on the co-operation of employers to set minimum wages in Hong Kong is a breach of his legal duty, says an application for judicial review filed yesterday. The application - filed by 51-year-old cleaner Chan Noi-heung, and legislators Leung Yiu-chung and 'Long Hair' Leung Kwok-hung - seeks to overturn the decision by Chief Executive Donald Tsang Yam-kuen to trust the setting of minimum wages and employment conditions to the market. Ms Chan claims that her salary is so low and conditions of work so bad that the chief executive should use powers conferred on him by the Trade Boards Ordinance to establish minimum conditions and pay for her industry. The ordinance states its purpose is 'to provide machinery for fixing minimum wages, determining normal working hours, and fixing overtime rates in trades where the wage standards are unreasonably low'. Ms Chan, who works for a Kowloon Motor Bus contractor, is paid HK$3,400 a month for a 10-hour day and has only four days off. She used to earn HK$4,000 a month, but when KMB switched contractors in December 2004, her pay fell to HK$3,700. That dropped to the present level - equal to about HK$13 per hour - last December. The writ claims that after paying HK$1,299 in rent for the 380 sq ft flat she shares with her 29-year-old son, HK$600 for utilities, and HK$2,400 for food and groceries, she is about HK$900 out of pocket each month. A Hong Kong Confederation of Trade Unions survey has shown the average pay of cleaners in KMB bus stations is HK$3,300, or HK$12.22 an hour, and the lowest average hourly wage HK$8.33, the writ says. Such low pay meant full-time cleaners were entitled to social security payments, the writ said. This meant taxpayers were subsidising the profits of KMB, the writ adds.