Shanker - it depends on many contexts i.e. discipline and overall competition in the area - as well as if employment is visa/scholarship-dependent etc. One thing that can be said, is that every quality publication increases your academic profile and the possibility of post-doc employment.
Try to become a member of international association/societies related to your work, and search for available post-doctoral fellowships. You could also attend major international conferences and introduce yourself to critical researchers/clinicians in your area and express your desire to do your post-doctoral fellowship in their labs.
Getting an employment opportunity after PhD is purely based on the knowledge that you have gained from your past research experience. Number of publications in well reputed journals may strengthen your profile and help you to be in the short list, but ultimately your knowledge will be the game changer. I hope you will get good opportunity soon. Keep on trying and never give up.