You can follow a systematic approach to resolve this issue. You may carry out an action plan wherein people's participation would be of core importance.
1. You can have brainstorming sessions with case studies related to the perils caused by late coming (give two instances of the happenings in your workplace and the way it has affected business/productivity/coworkers/benefits, etc.).
2. After the brainstorming session, you may formally have a meeting of the workforce (together or in batches as the strength permits) and read out the leave policy.
3. Post the announcement, pass a circular for the signature of all the attendees; those who are absent, their respective head should brief the same to the absentee on the next (present) working day, and signature on the circular to be taken accordingly.
4. Also, explain the leave application form to the employees, how it is to be filled, when it is to be filled, the criteria for leave sanctioning, who has the authority to sanction the leave, and so forth. (As silly as it may sound, many employees may not know the actual process, thus avoiding the procedure.)
5. You may also divide your days into quarter days (2 hours), and after three late marks, quarter day leave to be deducted from the annual leave.
6. Furthermore, you can include a variable in the salary called attendance allowance, maybe a nominal amount, but an amount worth earning for 100% attendance (no late marks allowed, but sanctioned leaves will be considered). Thus, the employees can earn the extra amount. If paying extra is a concern, then you may think of adding such a head in the present variable salary structure.
7. Also, you may put up a board and star against the employees coming on time and a red mark for those who don't and pin it up on the notice board.
Hope the suggestions can come to some help.
All the best for better attendance and retarding tardiness.
Regards,
Mugdha Mitbawkar.