Employees of pnb or sbi are govt employees?

Yes but not pure govt employees, they come under PSUs nationalized Banks,

Hi pure govt employees are directly employees of GOVERNMENT DEPARTMENTS DIRECTLY eg customs, service tax , police etc, pure govt employees of high level are also gazetted officers, 

whereas non pure govt employees are employees of banks, autonomous bodies, public private partnerships, PSU, etc where govt has major role / share. 

usually both pure and non pure govt employees have same payscales, but different powers ,