If your Diploma and recruitment are approved, you will need to get a medical done as well. A security check is also carried out on all Indian nationals. That is why it can take a long time to finalise matters and get ready to board the plane.
After arrival the Stage II is carried out i.e. the work permit is placed in the passport (within 30 days of arrival). There is also a 2nd part of the medical which is done in Malaysia i.e. a chest xray etc.