I don't know anything about the visa categories for Malaysia, but it's very common around the world to not permit a spouse or any dependents accompanying a working visa holder to work. One US expat group tried to get legislation passed in the US to allow dependents to work only if their home countries would allow US trailing spouses to work in their countries. But no one was really interested. (I suppose it is seen as just a further complication of the already pretty complicated visa laws in the US.)
Cheers,
Bev