As a fresh graduate going into labour market, can i be a millionaire working as a civil servant?

To be Frank, the answer is NO. Unless you want to be saving all your salary without touching it which is impossible unless you have other sources of income. For most government jobs, the salary range for fresh graduates is between 80K to 150K so you can do the maths.

This question appear very simple but technical and practical. If you have never been been a civil servant to the level of retirement you may not be able to answer it accurately beside the fact that working as a federal civil servant is quite different from state civil servant. You need to consider that Directors, Permanent secretary and Head of service are all civil servants and if you are able to rise to such levels in your civil service career, you are likely to be a millionaire but it will take you many years in the service. Another angle to this is the ministry or para statal you are working with, its easier making money in some establishment than others e.g. a classroom teacher employed by state cannot be compared to a custom officer at the border. I think it all depends on many factors but above all, it is possible for some while it is impossible for some.