Security guards and night watchmen are being forced to work 12 hours a day by employers who get away with it because jobs are scarce amid the economic downturn, a survey says. Long shifts were causing some workers to sleep at work, jeopardising the safety of residents in the event of fire or other problems, said the Buildings Management and Security Workers General Union, which carried out the survey in the past month. It found that 80.6 per cent of 420 employees questioned worked 12-hour days. Union spokesman Wong Ying-yu said there had been few lay-offs in the profession in the past year. But many of the estimated 150,000 people working in the field had been forced to increase their working hours from eight to 12 hours a day without adequate overtime pay. 'In one case, a company increased the hours from nine to 12, but only paid the workers an extra $500,' Mr Wong said. 'They're using the economic downturn to increase the hours because they know the workers would have a hard time finding another job.' By increasing hours, employers were saving money as they did not need to hire as many workers, Mr Wong said. The survey found about 55 per cent of the workers earned less than $6,000 a month and 15 per cent of them made less than $4,000 - or an average $12.50 an hour - less than what a typical fast-food restaurant worker earned. Fourteen per cent of respondents were not allowed to take holidays they were entitled to, including annual holidays - which is a violation of labour laws. The law requires that workers receive at least one day off a week, but the survey found 8.7 per cent of respondents had no days off and 10.8 per cent received less than the legal minimum. A large majority of those surveyed wanted the Government to limit working hours to eight a day and set a minimum wage of $35 an hour. Limiting work hours would create an extra 50,000 jobs and would help many unemployed people, union leaders said. However, a manager at Imperial Parking said the company's recent decision to raise daily hours from eight to 12 for its 100 car park guards was justified. The firm had paid the guards an extra $500. He said the company had had to cut parking fees at some car parks because some customers were threatening to go to a competitor.