Claiming Dual Nationality to work for Humanitarian / Aid agencies if you are only an English Speaker or not a civil servant on secondment to a UN department / IMF or European Institution:

Countries:
a) Australia
b) Canada
c) USA
d) New Zealand
e) Republic of Ireland
f) Republic of South Africa
g) Israel
h) Palestine
At present travel into Palestine is registered with Israel prior to the full establishment of a Palestinian state (unless via Jordan as it has a peace treaty with Israel).
i) Lebanon
This state is multi faith of Arab muslim, Latin Christian, Orthodox, Alawite, Marionite and in teh twentieth century Jewish in the south of the country.
j) Egypt
Egypt had in theory prior to the Arab Spring last year a secular law of nationality
k) Medditeranean Union

Faiths NGOs registered at the UN.
l) United Synagogue of British Commonwealth and United States
For claiming nationality of Israel under the law of return you need to be of jewish descent (ie born of Jewish mother or grandmother), or a recognised convert from a recognised Jewish sect, and or a 'key worker' on a work visa. The United Synagogue is the descendant sect from the group that agreed teh return to England under Cromwells commonwelath and those that aided teh translation into English of the books of the Bible that make up the Torah / Talmud / Mishnah (The Old Testament of the King James Bible). There are also the Haredi (Ultra Orthodox) who are exempted military service similar to some American Christian denominations and Jehova Witnesses, The reform (english language services), Liberal and progressive sects. Finally there are the Jewish Christians (termed 'Jews for Jesus) though whether Israel recognises them as opposed to non practising Jews (the secular / humanist categories)

m) Vatican
In an official capacity a practising Roman Catholic can serve overseas as a Vatican Official or as an advisor to the United Nations.

n) Worldwide Anglican Church / Church of England
The Anglican Church has a similar category as officials to or acting on behalf of The Archbishops Consultative Committee of the Anglican Church.

o) Civil aid agencies
aid missions and ships to Gaza or Lebanon and Syria coordinated by aid agencies registered globally and in recognised states and intergovernmental organisations (such as The European Union) have operated unarmed aid ships on a rule of delivering peaceful aid. However they are intercepted by armed boats from Egypt and Israel and Syria in varying scenarios.

The Knights order of St John of Jerusalem / Rhodes / Malta used to govern territory till the eighteenth / nineteenth centuries when these islands were claimed by 'nation states'. However like teh Nobel Trust they now work as aid agencies similar to the International Committee of the Red Cross / Crescent and Diamond with their first aid and humanitarian relief based on constituent organisations in nation states (such as the Red Crescent of Turkey, British Red Cross, Australian Red Cross and American Red Cross).

Given that their is now the risk of arms proliferation of nuclear weapons to Iran and that as a result Saudi Arabia and Bahrain and Egypt might seek to arm themselves similarly and then theres a triumvirate with Israel, it is better to write letters and get the IAEA to broker global nuclear disarmament of all weapons into Un regulated through the IAEA cvilian nuclear power rather than risk 'martyrs' like CND in previous decades. This is a matter for teh UN General Assembly / Security Council