Dear Aldrin,
I recommend not to look human resources in isolation. What you need to do is to do a process study. First map all the processes. Then find out whether any process overlap or process duplication is there. This will give you idea as to where wastage of human efforts is going on. Study of processes is the base for multi-skiling, cross-training etc.
The second thing you need to do is to fix the measures of performance for each department. Attainment of these measures is far more important. To attain these measures, what needs to be done that you do. It may mean upgradation of technology wherever possible. To do this activity, I do not think you require any external agency.
Last but not the least, you may do "Time and Motion Study". Yes, this is industrial engineering activity. For this you may require help of some external agency. But again as long as you do not do preceding two activities, going for the third one directly may not suffice the purpose.
Thanks,
Dinesh V Divekar