Dear Naveen,
Leave is only a welfare measure in the realm of employment so as to enable every employee discharge his personal and social obligations like any other member of the civilized society and as such leave, in general, cannot be claimed by any employee as a matter of right under any labor law. Therefore, an inherent discretion is always bestowed on the employer whether to sanction the leave applied for or not subject to exigencies of work. However, such a discretion of the employer also stands defined on the parameter of reasonableness by means of classification of leaves into various types such as Casual Leave, Sick Leave, Earned Leave and so on depending on the type of industrial establishment and some times by means of Collective Bargaining Agreements. Therefore, there cannot be any straitjacket answer as to effective handling of the issue of any particular employee availing frequent leave of a particular type.
Just because of sufficient credit in the leave account, if an employee indulges in entering on sick leave very frequently or periodically, it can be an indication of feigned reason to thwart the process of prior sanction. The letter of warning as mentioned in the post is a reasonable one.If the same practice is repeated, the leave applied for can be refused and the absence may be treated as unauthorised one resulting in loss of pay and break in service subject to availability of such a clause in the service regulations or standing orders applicable.