Kranjska Gora Mayor Jure Žerjav said the latest version of the route was unacceptable, as it passes through the narrow Alpine valley upstream along the River Sava, including the Triglav National Park, Natura 2000 areas and the Zelenci protected area.

"My personal opinion is that in such a narrow Alpine valley...building a gas pipeline is almost impossible...The pipeline would cut through protected areas in multiple sections," he told the press.

The final route of South Stream has not been determined yet, but a map on the website of Russian gas giant Gazprom, the principal investor, shows it turning north near Ljubljana towards Kranjska Gora, a popular tourist destination, and into Italy near Tarvisio.

This coincides with a main road running from Jesenice northwest to Mojstrana, Kranjska Gora and on to Italy.

Žerjav said representatives of the Urban Planning Institute had been in Kranjska Gora at the end of October unofficially presenting that the pipeline will run through the municipality.

The mayor said the planners should stick to the original plan and direct the pipeline south, towards Šempeter, a town on the border with Italy some 50 km south of Kranjska Gora, "to avoid delays in such a major project".

Žerjav said his concerns were upheld by the municipal council. He also raised the issue with competent ministries, but none have replied so far.

He has therefore decided to petition the government, "in the hope that the valley is preserved."

His statement came just hours after Slovenian state-owned company Plinovodi signed an agreement with Gazprom during a visit by Prime Minister Janez Janša tu Russia.

The a deal on the final investment decision of the shareholders of the company South Stream Slovenia constitutes the final approval of the construction of the Slovenian part of South Stream.