The launch of the EU-backed gas pipeline project Nabucco may be postponed by another year to 2018.

Gerhard Roiss, CEO of Nabucco shareholder OMV, was quoted Tuesday as saying that first gas supplies would flow through Nabucco in 2018 and that this "was the latest information which we have."

The announcement cited by Austria Press Agency (APA) increased the delay to a total of 3 years, given that the completion of the gas conduit was initially scheduled to go into operation by 2015.

Approached to comment on the issue by journalists of Dnevnik daily, Nabucco Gas Pipeline International GmbH stressed that the project implementation schedule was contingent on the availability of sources of gas supplies.

The international project company explained that it would soon come up with a a decision on the development of the Shah Deniz II field.

The Nabucco consortium went on to confirm that the start of construction works was still planned for 2013 and that no delay was expected at this stage.

The project aimed at alleviating Europe's dependency on Russian gas has been struggling to secure suppliers and has already had to postpone construction a number of times.

OMV's chief executive Roiss is touring central Asia this week to negotiate supply deals for Nabucco and has already met Monday with Turkish Energy Minister Taner Yildiz.

On Wednesday, the CEO of the Austrian oil and gas giant signed a memorandum of understanding between OMV and Azerbaijan's state oil company Socar on joint energy projects.

Nabucco, which faces stiff competition from rival pipelines including Russia's South Stream, is to bring up to 31 billion cubic meters of gas a year from the Caspian region to Austria via Turkey, Bulgaria, Romania and Hungary.

OMV is one of six equal-share partners in Nabucco alongside Bulgaria's BEH, Hungary's MOL, Romanian Transgaz, Turkish BOTAS and RWE from Germany.

Each of participants has equal share to the amount of 16.67 percent.

Talks are underway with Bayerngas GmbH, a publicly owned German-Austrian gas procurement vehicle which expressed interest in joining the project as a seventh shareholder.

The company has not specified the stake it intends to acquire in Nabucco.