Government letters marked confidential

I am dealing with a lot of Government departments and see that every letter that comes to our company is stamped ‘CONFIDENTIAL’ or in Swahili ‘SIRI’. What are the implications of such words in correspondences with the Government? Is this something that can cause problems for the recipient of these letters? I have noted that even some letters that have no confidential content in them are marked confidential or siri. How do I know which is which?
AK, Moshi

Once a letter from the Government ministry, agency or institution is stamped with a stamp bearing the words ‘confidential’ or ‘siri’, it means the information contained in that letter is regarded in term of section 5(1) of the National Security Act [Cap.47 R.E 2002] as classified and holder of such information is not allowed to communicate or leak the information contained in the letter to any person other than a person to whom he is authorised to communicate to or a person to whom he has the duty, in the interest of the United Republic, to communicate. Leakage or communication of the contents of the letters from the Government marked ‘confidential’ or ‘siri’ constitutes a serious offence which attracts imprisonment of up to 20 years. It does not matter how many letters marked ‘confidential’ or ‘siri’ you received from the Government, you are still bound to make sure the information contained in those letters are not leaked or communicated to a third party.