You must have settled down in your own company as a director. Though your thread is very old, I would like to respond so that this discussion may bring some value addition to our knowledge.
Implied Conditions in Employment
Even though there is no written contract between you and your employer, no appointment letter is issued to you by your employer, or there is no specific clause in the appointment letter, certain conditions are implied on your appointment. Accordingly, when you accept any employment, you are supposed to perform your duty wholeheartedly. If you involve yourself in other activities outside of your employment, it definitely affects your employment. Therefore, the employer can object to such activities outside of your employment. If there is any conflict of interest due to such activities, the employer can even take appropriate legal steps against you.
I invite other members to discuss this issue.