Two former executives of a cleaning company and a sub-contractor have been jailed two years by the District Court for extorting $1.9 million in wages from workers.

Au Wai-hung, 46, a former general manager of Polyking Services, pleaded guilty to one count of conspiracy to defraud.

Leung Chi-keung, 38, a former accounts manager of Polyking, and So Wai-hung, 47, a cleaning subcontractor for the firm, were found guilty on one joint charge of conspiracy to defraud. Leung was further convicted of a similar offence of conspiracy to defraud.

On July 1, 2002, Polyking was awarded a Leisure & Cultural Services Department contract worth $9.42 million for the provision of cleaning services to Central Library for two years.

The contract stipulated that Polyking had to pay each day-shift worker a monthly wage of not less than $5,166 while each night-shift worker should receive not less than $3,228. Since the commencement of the contract, Au instructed a contract manager of Polyking to recruit day-shift workers at a monthly wage of $4,500, and night-shift staff at $2,500.

The court also heard that on November 1, 2003, Polyking secured another $17.8 million contract for providing Kowloon Park with cleaning services for months. At the outset, Polyking subcontracted the work of the swimming pool to So, who took up the entire Kowloon Park cleaning services from April 2004 onwards. According to the contract, the workers should have been paid a monthly wage of $5,190. Instead, Au instructed So and the contract manager of Polyking to recruit cleaning workers for $4,300.