Think you've got the world's toughest boss? You might not be far off.

A survey by Robert Half International found that 97 per cent of Hong Kong employers expect their staff to be available after office hours. Of those, 35 per cent also require workers to be on call during annual leave.

The findings varied considerably to survey results from other jurisdictions, such as New Zealand where 39 per cent of employers called for no after-work availability whatsoever.

Andrew Morris, Robert Half's managing director for Greater China, says the discrepancy can largely be attributed to the city's role as an international banking hub.

"Hong Kong is the second largest financial services district anywhere," he says. "That being the case, it's very competitive. And in a very competitive operating environment, companies usually demand a lot from their employees. The by-product of that can be a very stressful working environment.

"Banks tend to make really fast decisions. They can be working on deals worth hundreds of millions of dollars. And when you're working on projects that can have that high an impact on the bottom line, you tend to have a high level of accountability."

While this may produce strong performance in the near term, the benefits may be short-lived, Morris explains.

"At the end of the day, it's a double-edged sword. They may get very good results. But in the long run, it's going to hurt retention efforts, it's going to hurt company culture. Most importantly, it's going to result in [employee] turnover."

This is by no means an issue to take lightly - particularly in a city such as Hong Kong where an earlier Robert Half survey found the turnover rate to be six months shorter than elsewhere.

The financial repercussions of a high turnover may be higher than some think. According to Morris, the actual cost of replacing a tenured staff could be up to three times their annual wage after factoring in the training period and loss in productivity.

Performance declines among those who choose to fight through the hardships could also be an issue. Eventually, Morris explains, employees subject to excessive working hours are going to get stressed, since they're never able to switch off. "If you keep working them that way over a number of months or years, productivity is eventually going to drop," he says.

Morris suggests companies put in place better communication channels between staff and management. He also recommends training and assigning staff to fill in for others while they're out of the office.