"We are not continuing the talks," a spokesman for the Bavarian company told Reuters, adding Bayerngas was adjusting its strategy and was more focused on investing in pipelines in Germany.

The Azeri gas and oil producer consortium Shah Deniz is expected to choose by mid-2013 whether to transport gas from its fields via the Nabucco-West pipeline or the rival Trans-Adriatic pipeline (TAP) into western Europe.

Bayerngas had been talking to the consortium since October 2011, but delays, possible cost overshoots and rival pipelines lessened the attractiveness of the plan, according to some critics.

Nabucco's current five shareholders are Austria's OMV AG , Hungary's MOL through its gas pipeline operator FGSZ, Turkey's Botas, BEH of Bulgaria and Romania's Transgaz, after German RWE recently pulled out.