FACTBOX - Key facts about Myanmar's constitutional vote

(Reuters) - Myanmar's junta went ahead with voting on Saturday for an army-drafted constitution even as the government and international agencies struggled to get aid to an estimated 1.5 million people in need after Cyclone Nargis struck a week ago.

The referendum is being held in all but the worst-affected parts of the southeast Asian country. The plebiscite would be held in the Irrawaddy delta and the biggest city of Yangon on May 24, the government said.

Here are some facts on the vote and proposed constitution, which would be the third since the former Burma gained independence from Britain in 1948.

* The constitution is a key step in a seven-point "roadmap to democracy" announced by the junta in 2003. The roadmap is meant to culminate in multi-party elections in 2010 that will end nearly five decades of military rule in Myanmar.

* The 200-page constitution and commentary makes the army commander-in-chief the country's most powerful figure, able to appoint key ministers and take power "in times of emergency".

It gives the military a quarter of the 440 seats in parliament and a veto over legislators.

* It bans Myanmar nationals with foreign spouses or children from political office -- a clause said to prevent the election of democracy icon and leader of the opposition National League for Democracy (NLD) Aung San Suu Kyi. Her husband, now deceased but with whom she has two sons, was British.

* The constitution was drafted by a 54-member commission of mostly military officers and civil servants hand-picked by the junta in October 2007. It has been widely-derided by the opposition and Western governments as a blueprint for the generals to cement their grip on power.

* The NLD, whose 1990 election victory was ignored by the junta, have called for a "no" vote on the charter, as have other dissidents. The NLD sporadically boycotted the laborious 14 years of talks at a National Convention that preceded its drafting, calling the process undemocratic.