Dear Zaheer,
Other senior members have given valuable comments. Now let me say something from organisation's culture point of view.
When employees go on unplanned leave it only goes on to show their priorities. They give priority to their own affairs rather than company's. We need to fix this mindset.
Why employees are so nonchalant to company's requirement? How management deals with them? Is the dealing fair and square? Are the systems and processes well defined? If yes, are these implemented properly? How is the remuneration? Is it as per market standards? Is it that your company finds great difficulty in getting the right people? Now your employees have understood that and they can take risk playing truant?
How managers deal with the staffs? How is the interpersonal environment? What is that unique you have done to develop employees' attachment towards the company?
I recommend you taking feedback from employees on improving the company's culture. For this of course, you leadership may need to change the leadership style. Obtain this feedback if the leadership is ready to change their behaviour also? For doing various organisation's surveys, you may take help of humanlinks.com
Thanks,
Dinesh V Divekar