Project companies backing Nabucco West, a scaled-down version of the larger $10 billion pipeline, and the South East Europe Pipeline handed in proposals to the BP-led consortium managing the Shah Deniz natural gas field in Azerbaijan in May.
Both projects are part of the Southern Corridor of transit networks designed to break Russia's grip on the regional energy sector.
Wolfgang Sporrer, regional manager of Austrian energy company OMV, told an international oil and natural gas symposium in Baku that Nabucco shareholders believe Nabucco West is the most strategic and flexible option within the Southern Corridor.
"We believe that Nabucco West finally brings together strategic interests of shareholders, European consumers and bring together interests of producers," he was quoted by the regional Trend news service as saying.
OMV is a member of the Nabucco pipeline consortium.
Project partners said they expect the second phase of the Shah Deniz natural gas field to start production by 2017.