Kalfin made the remarks during the opening of the first national conference on energy and climate change held in the Bulgarian capital of Sofia.
His comments came in response to Monday's report in the Russian newspaper Kommersant claiming that Russia's Gazprom might select Romania instead of Bulgaria as its partner for the South Stream pipeline.
The paper said at the end of last week that Gazprom chief Aleksei Miller met in Moscow with representatives of Romania's Transgaz and Rompetrol.
The Bulgarian government and especially Energy Minister Petar Dimitrov wanted to make the Bulgarian state the owner of the South Stream pipeline on Bulgarian territory, whereas Gazprom insisted it should own the facility, the paper noted.
Kalfin said there was clearly competition on the energy market in the region including with respect to natural gas deliveries.
"However, I do believe that as far as South Stream is concerned Bulgaria is far ahead of its neighbors. We have signed a contract, it is clear, and it is being acted upon, so there is no need and no motive for pressure for anything," Kalfin explained.
The Bulgarian Ministry of Economy and Energy said work on South Stream is progressing quickly and in accordance with the intergovernmental agreement between Bulgaria and Russia, and there are no grounds for concern on the Bulgarian side.
Bulgaria and Russia signed the agreement for the construction of the South Stream pipeline, widely seen as competitive to the EU-sponsored Nabucco, during former Russian President Vladimir Putin's visit to Sofia in January 2008.