Baltic States – CIS, Energy, EU – Baltic States, EU – CIS, Gas

He said it had been pushed through "over our heads" and did not make economic sense – Warsaw has repeatedly insisted that the consortium has failed to explain why a sea route is better than a cheaper land option, writes AFP/ELTA/LETA.

Sikorski has long been a vocal opponent of the pipeline. He caused a stir in 2006 when he said it echoed the 1939 Molotov-Ribbentrop Pact under which Nazi Germany and the Stalinist Soviet Union carved up Poland at the start of World War II.

The 7.4-billion-euro (10.7-billion-dollar) Nord Stream project is led by Russian state-run energy giant Gazprom in partnership with Germany's E.On Ruhrgas and BASF-Wintershall.

The 1,223-kilometre (758-mile) project would link the Russian city of Vyborg and Greifswald in Germany, running through Russian, Finnish, Swedish, Danish and German waters. The consortium has said it aims to begin pumping gas by 2011.

Poland and other ex-communist Baltic Sea states such as Estonia and Lithuania, whose relations with Moscow are rocky, have warned that the pipeline will increase Europe's direct dependence on Russia for natural gas. Critics claim the Kremlin uses its energy clout as a political tool.

They have also criticised fellow European Union member Germany for allegedly sidelining their concerns over the plan and forging ahead.

Moscow counters that the pipeline will help prevent a repeat of the Russia-Ukraine gas crisis which severely disrupted supplies to Europe in January 2009 since it would by-pass such transit countries.

Russia has also claimed Poland's opposition is rooted in anger that it will not get transit fees from the sea-based pipeline.