From the ICAO
website
Does my licence meet ICAO requirements?
Some States include a statement on the licence specifying that the licence meets the requirement of ICAO Annex 1 to the Chicago Convention. When it is not the case, licence holders may verify with the Civil Aviation Authorities in their respective States whether their licence is in compliance with ICAO requirements. Each individual Contracting State should have the information available as they have the duty to inform ICAO of any difference between ICAO licensing Standards and their national/regional regulations. Any information in this matter submitted by Contracting States to ICAO is contained on the Supplement to Annex 1.
Non-ICAO compliant licence
1. An endorsement with a "Licence does not meet ICAO requirements" statement may appear on a licence in two different situations:
a. the licence covers an activity for which no ICAO licensing requirements exist. Typical examples are airship, microlight or recreational pilot licences; or
b. the licence covers an activity for which ICAO has established licensing requirements but the holder does not meet all conditions related to age, knowledge, experience, instruction, skill and medical fitness.
2. Licences that do not meet ICAO requirements are not recognized internationally and are therefore valid only in the airspace of the State that has issued such a licence. The use of the licence in other States is only possible if the State whose airspace is used, has authorized it.
For more information, please refer to Annex 1, Chapter 1, paragraphs 1.2 and 1.2.5 and the FAQ on "International recognition of flight crew licences".