* Gulf Arab leaders choose Saudi Arabia to host joint c.bank
* UAE says it has "reservations" about the choice of Riyadh
* No decision yet on when single currency will be launched
(Changes paragraphs 2, 9, 11-12 with UAE statement)
By Souhail Karam
RIYADH, May 5 (Reuters) - Gulf Arab leaders on Tuesday chose the Saudi capital, Riyadh, as the base for a joint monetary council that will evolve into the Gulf central bank, although they were still undecided on when to launch a single currency.
But the United Arab Emirates, one of the major candidates to host the bank, said afterwards it had "reservations".
Top state officials from Saudi Arabia and its neighbours in the world's biggest oil-exporting region agreed the move at a meeting called to lend credibility to a plan for a single currency that member states have agreed to delay beyond an initial 2010 deadline.
"An agreement was reached on the headquarters of the monetary council that it should be in the city of Riyadh," said GCC Secretary-General Abdul-Rahman al-Attiyah.
"Concerning the timeframe, no decision has been issued yet on the currency," Attiyah told reporters, later adding the central bank would also be based in Riyadh.
The Gulf needed to choose a venue before a monetary council could begin operating, but the decision has been caught up in political wrangling for the past year.
This council will decide on a new timetable to issue the single currency, the GCC-Secretariat said in March, its first official acknowledgement the Gulf would fail to meet the 2010 deadline.
The GCC also includes the UAE, Bahrain and Qatar.
The Gulf monetary union plan lost credibility after Oman decided in 2006 not to join and Kuwait severed its dinar's dollar peg in 2007, breaking a deal to keep it intact until union.
"The UAE delegation to the 11th GCC consultative summit has expressed reservation at a resolution for selecting Saudi capital Riyadh as headquarters of the GCC Central Bank," a brief news item said on the UAE state news agency WAM.
Analysts have pointed to travel restrictions that foreigners face in Saudi Arabia, the largest Arab economy. The conservative Islamic state already hosts the GCC Secretariat itself. The UAE by contrast is a cosmopolitan trade and tourist hub.
POLITICAL WILL
"This announcement is a tangible signal of the political will to move ahead with the project," said Giyas Gokkent, chief economist at National Bank of Abu Dhabi.
"This all boils down to political will and the very fact they have agreed on the location is positive."
Saudi Arabia, the world's top oil exporter, is the largest economy in the Arab world and hosts the region's most influential central bank, whose balance sheet is more than eight times the size of its counterpart in the UAE.
A Reuters poll of 21 economists and analysts this week said Saudi Arabia was the most likely choice for the headquarters, ahead of Bahrain and the UAE, both of which have well-developed financial centres.
"They are recognising the significance of Saudi Arabia as an economy and the importance of Saudi Arabia to pull the other countries along," said John Sfakianakis, chief economist at SABB bank, HSBC's Saudi affiliate.
"They need size to push ahead with the effort. The Saudis need to create momentum."
The UAE, Bahrain and Oman had opted not to send their heads of state to the meeting in the Saudi capital, Riyadh. UAE Vice President Sheikh Mohammed bin Rashid al-Maktoum, Bahrain's crown prince and Oman's deputy prime minister attended instead.
Gulf policymakers have said global financial turmoil and a collapse in oil prices have made achieving monetary union more urgent.
(Writing and additional reporting by Daliah Merzaban in Dubai; editing by Stephen Nisbet and Ron Askew)