Dear Aarti,
Provide classes on the importance of punctuality and other motivational aspects.And then prepare policies in order to stop the late coming and absenteeism.
For example,
In punch late by 15 minutes-3O minutes salary will be cut
Early out punch by 15 minutes-3O minutes salary will be cut
and create system where in they have the employees have to enter their late coming details and early leaving details has to be entered and get approved by their immediate head,else their full day salary will be cut.And also if there is no 8 hrs presence in the office without approval from the immediate head through the system ,an employee won't get that day's salary.
Incase of uninformed absence,you should consider it as absence.Don't let them apply for leave.
These are the only ways to stop this practices and bring discipline in the office
Regards,
Anita George