I just got into mindef, sharing some experiences.

Sometimes, they are considering other candidates(Can be internal or external) so the HR won't be able to give you a reply.

Also at the same time, they will compare ur test results to see if it is a fit for the role. Other thing is that the clearance can take months.
The HR will give a verbal discussion on offer if it is already at final stage.
But be prepared, clearance is quite long, so you might be hired into another company before ur clearance is done.