Well, there is a difference between part-time staff and
temporary staff...
Working hours are usually determine by the company. Full time
staff usually works for longer hours in a week. Part time simply
does less hours (less shift or half duration shift) in a week.
Those that come when needed are called Temporary staff.
It's quite normal since the hiring company determines the shift
and roster...
The only advice is, if you are uncomfortable then dun sign up
with them, look elsewhere for job...
