HONG KONG - Employers here who want to hire foreigners for jobs such as nursing home caregivers and mechanics have to jump through three hoops.

First, they have to embark on a mandatory four-week recruitment period within Hong Kong.

During the first two weeks, employers looking to fill these "technician-level or below" positions have to advertise the vacancies at least once a week in two local newspapers. They must offer wages no less than the industry's prevailing median level.

Second, the government's Labour Department will concurrently try to match the vacancy with local job-seekers. And if necessary, employers have to organise tailor-made training programmes for local workers, with the assistance of the government's Employees Retraining Board.

The last hurdle comes at the end of the exercise, when employers have to provide the Labour Department with information on their recruitment efforts. If no local workers are found at this point, the firm can apply to bring in foreigners. The application will be considered first by the Labour Advisory Board and then approved by the Labour Department.

Called the Supplementary Labour Scheme (SLS), this process was put in place in 1996 when Hong Kong was facing a labour crunch and needed to bring in foreign workers. The idea was that by regulating the inflow, the job prospects and wage levels of local workers would be protected.

A worker admitted under the SLS can work in Hong Kong for a maximum of 24 months under each employment contract. As of the end of last year, there were 2,415 workers under the scheme.

Employers who want to hire foreigners to fill professional-level jobs apply under a separate, and less stringent, General Employment Scheme (GES), administered by the Immigration Department.

The more liberal regime - there is no mandated local recruitment period, for instance - has led to problems. In one case in 2011, unions complained some firms were circumventing the SLS by applying under the GES. An example cited was the Hong Kong Aircraft Engineering Company, which stopped applying to bring in mechanics under the SLS, but tried to do so for "aircraft-maintenance licensed technicians" under the GES instead. Critics said the nature of the jobs was the same.

The government has since sought to have both departments work more closely on permit approvals.