Poland has decided to freeze its participation in a four-country project to build a new nuclear power plant in neighbouring Lithuania, state energy group PGE said Friday.

"Given the conditions, which have turned out to be unacceptable at the current point, and given our group's other key projects, we have decided to freeze our participation in this programme before making any formal commitments," PGE's head Tomasz Zadroga said in a statement.

PGE is in charge of Poland's own atomic power programme, and is poised to launch the tendering process for the country's first nuclear plant, which it aims to bring online by 2020.

Lithuania closed its only nuclear power plant, a Soviet-era facility at Ignalina near Visaginas in the Baltic state's northeast, on December 31, 2009, under the terms of its European Union entry four years earlier.

Lithuania had tried and failed to convince Brussels to let it keep the plant open until the replacement at a nearby site was ready.

The new facility is also meant to be online by 2020, generating 1,300 megawatts.

But progress has proven sluggish in the project, which besides Lithuania and Poland also involves fellow 2004 EU entrants Latvia and Estonia.

The project has also been dogged by discord among the four countries about their relative stakes in the project and future share of the power generated.

Last December, the bidding process had to start afresh after South Korea's state energy firm Korea Electric Power Corp., which had been chosen for talks, unexpectedly pulled out.

In July this year, Lithuania invited Japanese-US conglomerate Hitachi GE to start talks on building new plant.

The old plant provided 70 percent of the electricity in Lithuania, which has had to boost its use of gas-fired power stations as a result of the closure.

Lithuania still relies on Russia for all its gas.

Its ties with its Soviet-era master have been rocky since independence in 1991, and this year it has been locking horns with Russian gas giant Gazprom over pricing.

In another Soviet hangover, Lithuania lacks power supply links with western Europe. There are plans to hook it up to Sweden's grid and to Poland.