Bulgaria now meets almost all its gas needs with imports from Russia's Gazprom and the new gas link is crucial to its weaning off Russian gas, which is also a key priority in Europe's reviewed energy policy following Russia's invasion of Ukraine.

The 220-million-euros Interconnector Greece-Bulgaria (IGB) was planned to have been ready by the end of 2020 after hitting several administrative hurdles in recent years.

The long-delayed pipeline will be operational in September, Bulgarian Prime Minister Kiril Petkov told reporters after inspecting the construction site with Greek Energy Minister Kostas Skrekas in the Greek town of Komotini.

"June will be the final date for the completion of this project, which is very important for us," he added.

Bulgaria, where annual gas consumption is about 3 billion cubic meters (bcm), has sealed a deal to receive 1 bcm of Azeri gas but can only fully tap the contract after IGB becomes operational.

The 180 kilometer-long pipeline is being built by a joint venture of Bulgaria's state energy company BEH and Greece's gas utility DEPA and Italy's Edison. It will have a capacity of 3 billion cubic metres (bcm) which can be increased up to 5 bcm.

Bulgaria said last week it will not hold talks with Russian energy giant Gazprom to renew its gas purchase deal and will be looking at alternative supplies.

"We do not plan to cut off Gazprom in general, we do not have such ideas, but the question is when we enter into talks to know that we have more than one card in our hands," Petkov said.

(Reporting by Angeliki Koutantou in Athens and Tsvetelia Tsolova in Sofia, editing by Ed Osmond)