You have written that the employees in your company do not adhere to the shift timings. However, what exactly happens that you have not mentioned.
Who makes the shift roster, when it is made and how many days before it is made? What is the means of communication of the shift roster to the employees? What are the shift timings and are the shifts rotated? Is policy of rotation applicable to all or certain persons are given exemption?
Do employees report late for their duties? For their late-coming, do you follow the rules that are in vogue or you have your own set of rules?
There are so many questions associated with your post gentleman. Please give complete information. Suggestions can be given only thereafter.
From India, Bangalore
Since you said you joined recently first be a part of your employees and you will understand the reason for not adhering to shift.
1) Try to know whether it was informed during employment
2) Ask shift supervisor if he has the information from operator but it my look like indisciplane to you as you dont have that info.
3) Call supervisor and say shift list has to be submitted as it is necessory.
After your feedback I may write once again to you.
From India, Bengaluru