Nabucco and TAP gas pipelines could both be built one day -TAP

* Second pipeline could take another five-to-10 years

* Decision on winning project expected by mid-2013

BRUSSELS, Feb 13 (Reuters) - Both of the projects vying topipe Azeri gas to the European Union can be built but not yet, asenior official from one of them said on Wednesday.

The governments of Albania, Greece and Italy on Wednesdaysigned an agreement, confirming their support for the TransAdriatic Pipeline (TAP), one of two projects in competition toreduce EU dependence on Russian energy.

"There will be 10 billion cubic metres of gas available fromShah Deniz phase II. In that context, there can't be twolarge-scale pipelines built at the same time," TAP ExternalAffairs Director Michael Hoffmann told Reuters.

"But we can have two pipelines in a sequential situation. Itwill only be a matter of time before more gas comes on streamfrom Azerbaijan, though this may possibly take another five to10 years."

TAP is proposing a route through Albania and Greece intoItaly, while the rival Nabucco West project would ship gas alonga different path from Turkey's western border into a hub inAustria from whence it could be distributed.

Heavily indebted nation Greece is particularly in need ofthe kind of investment an energy pipeline would bring and GreekPrime Minister Antonis Samaras attended Wednesday's signingceremony in Athens.

The European Commission is project-neutral, saying its onlyconcern is that a route, which it refers to as the Southern GasCorridor, will be opened up to make EU supplies more secure anddiversified by providing a link to the Caspian region.

European Commissioner Guenther Oettinger in a statementwelcomed the signing of Wednesday's intergovernmental agreementas "an essential step".

TAP's shareholders are Swiss energy company Axpo (42.5 percent), Norway's Statoil (42.5percent) and E.ON Ruhrgas of Germany (15 percent).

Its rival Nabucco West includes Austria's OMV, Hungary's MOL, Turkey's Botas and Romania's Transgaz.

The Shah Deniz consortium, which comprises BP,Statoil, Azeri energy company SOCAR and Total, has a50-percent equity option in both rival projects. It is expectedto choose one of the two pipeline contenders by mid-2013.

Greece, Italy and Albania had signed a preliminary agreementto back TAP in September last year.