I suspect that the answer is that the only body with legal power over an NAA is the Government of which it is part, either directly or as an agency (eg the UK CAA).
Neither the UN nor any subsidiary organisation such as ICAO has any legal or regulatory powers in the Member States.
I very much doubt that expulsion from ICAO or the UN, or any form of sanction, is possible; if Flying Lawyer is around he could help.
ICAO issues SARPS; they do not become legally binding in a Member State unless and until they are brought into that State's law.
When EASA adopts a SARP, normally after a time-wasting, time-consuming, unnecessary "rule-making" process to justify their existence, stretching into years of bureaucratic nonsense, it becomes law in Member States by the operation of their Treaties with the EU and/or EASA.
There's nothing to stop you writing to ICAO, and/or the Government of the State you are talking about, setting out your concerns; substantial and conclusive evidence is recommended if you want it to go anywhere. If the State concerned has not brought whatever you are referring to into its Law, the situation is complicated.
Blacklisting of Operators, by a State or a group of States such as the EU, rather than sanctioning ICAO Member States, is another matter which is outside ICAO's remit.
Last edited by Capot; 13th Apr 2017 at 14:54.