Hello Palak
What I understand from your post is that there are some employees who do good work when the mangers are around and you seek to know how to supervise them so that they keep doing the good work. They may pose a problem if they are allowed to let off because the hard working employees may catch their habit fast.
It can be inferred from your post that the employees are competent to do their job and can do good job .I therefore do not visualize that there is any need to coach them as to how to do a job. They may be just lazy, whiling away their time in the office
Since your immediate concern is to know as to how to supervise them, I confine myself to this issue without going into issues of motivation etc. My suggestions are :
1) Call a meeting of all such employees. In the meeting, it is necessary to impress up on them that the company means business and that it expects every employee to contribute to the business and views such contributions as important and desires that the tasks are completed within the time lines and therefore decides to review and assess the performance of the employees.
2) Thereafter provide a written description of the tasks expected to be performed.
3) If it is so needed, explain them as how is to be done. Explain as to how and whom to coordinate with, the quality standards to be maintained etc.
4) Stipulate deadlines for completing the tasks.
5) Thereafter, at specified intervals f time, go to them to enquire whether they need any help. Do not frequently visit them or give them the impression that you are standing behind them breathing down their neck. They may not like it. Allow them the freedom but cast up on hem the responsibility for completing the task.
6) If any employee is not able to meet the time line, you can have one to one discussion with him the reasons for the same and address them. This sends a message that the management is serious about performance.
What is important is in dealing with lazy employees or deliberate work-shirkers is that the management has a serious business to do and they are employed in a workplace but not invited to a garden and that they need to contribute to the business for which they are paid.
B.Saikumar