Yes, you can get a government job after completing your engineering in diploma but make sure you have good knowledge for the subject. 

There are many government owned companies like BHEL, BEL, NTPC, Coal India, HPCL, Airport Authority of India, IITs, ECIL, BPCL, Government PSU like UCI, NACL, NLC, SAIL, NTPC, IOCL, ONGC, Power Grid, Railtel, NMDC, RITES etc offer positions to the diploma holders across the country.

Good Luck!!