The wine industry is facing a labour shortage

A new survey has found that Australian workers are annually losing about AU$21,500 due to clocking in unpaid overtime.

The survey by Unions NSW said about 9 in 10 employees put in overtime. These employees put in nine more hours a week on average, which adds up to more than 11 weeks of unpaid work annually for their employers, 9News reported.

It also found that people earning less than AU$70,000 annually were working about 7.3 hours per week of overtime. Meanwhile, workers in low-paying industries such as retail, hospitality and clerical were reportedly doing over six hours of overtime per week, which was unpaid. The education sector averaged the highest amount at 12.2 hours.

Nearly 5,500 workers from a variety of sectors were polled by Unions NSW, and the results showed that 64% of them felt they had to put in more hours at work to avoid having their future options limited, according to The New Daily.

According to the Unions NSW survey, no other Organization for Economic Co-operation and Development (OECD) countries' citizens put in these many hours.

"Unpaid overtime has been justified as a trade-off for higher salaried wages, or a necessity for junior employees in professional occupations with potential for high bonus or promotion opportunities," the Unions NSW report stated, according to 9News.

But, the report has challenged such justifications, saying that type of employment or wage or the industry have minimal to no impact on the overtime the employees work.

According to two-thirds of workers, their supervisors depended on this unpaid overtime, and many were afraid that turning down more work may impede their ability to advance in their careers.

According to one respondent: "If I assert my right to work during work hours only, I'm compared to younger colleagues who work extended hours to please the boss and have family support. ... I feel alienated from the staff that are in the office as this work style is forced to become the norm."

The Unions NSW has urged the government to take the necessary steps to boost employee rights, including a mandated four weeks of leave annually and strict documenting of overtime.