Dear Ms Rekha,
Do you use counseling for correcting errant employees ? If no, then please start counseling those who don't adhere to defined policies and procedures, rules and regulations which are uniformly applicable to all. There are instances when counseling has helped many to correct their ways, apply a human approach to such situations first.
Also, its better to have written notices (with prior approval of management) distributed to all concerned either by way of intranet email or hard copy circular posted on the staff notice board before taking an action against anyone.
Taking any stringent action must be preceded by warnings both verbal and documented.
Adopt the most appropriate solution / advice which suits you most out of the numerous replies that you may receive for your query.
Regards
Debashis