Yes, it is possible to hire students without paying them minimum wage. 

A student employee is exempt from the Minimum Wage Ordinance. To qualify as a student employee, the student must be a Hong Kong resident enrolled in full-time education.

There are 2 types of student employees, including the work experience intern and the student internship. The main difference is that the former requires the internship to be arranged or endorsed by their educational institutions and form a compulsory or elective component of their programmes, but the latter does not. 

Before their internship commences, an internship agreement should be signed by the employer and the intern. Additionally, the student employee must complete the confirmation of student status and additionally, a statutory declaration if they are a work experience intern. You should also keep a copy of the document(s) for record-keeping purposes.