Lithuanian lawmakers stepped up the pressure on the European Union Monday by calling a referendum to delay the EU-agreed closure of a Soviet-era nuclear plant that provides the bulk of the country's power.

Eighty-seven members of the country's parliament decided to call the plebiscite on October 12, when Lithuanians also go to the parliamentary polls.

Only five lawmakers opposed the move to postpone the shutdown of the aging plant at Ignalina in eastern Lithuania, due at the end of 2009.

"Our motive is the difficult situation facing Lithuania. After Ignalina is closed, electricity prices will rise fourfold," said Vytautas Bogusis, the opposition centre-right lawmaker who piloted the referendum bill.

"In 2010 the situation is going to be catastrophic," he told AFP.

Holding the referendum is purely symbolic because the result would have no legal value. But the goal is to beef up Vilnius' negotiating position in talks with the European Union as it seeks a delay, Bogusis explained.

The pledge to close Ignalina by the end of 2009 was one of the conditions for Lithuania's admission to the EU in 2004, 13 years after it broke free from the crumbling Soviet Union.

Ignalina, built in 1983, is the same kind of nuclear plant as Chernobyl, which caused the world's worst nuclear accident when it exploded in 1986, contaminating parts of Ukraine, where it was located, as well as Belarus and Russia, then all part of the Soviet Union, and western Europe.

One of Ignalina's reactors was shut down in December 2004, but Lithuania fears that closing the second before a new plant has been built will cause major power shortages. Ignalina provides 70 percent of the electricity in this country of 3.4 million people.

Vilnius is concerned that Lithuania will be left totally dependent on energy supplies from its communist-era master Russia, at a time when relations with Moscow are at their frostiest in years.

Lithuania is in talks with neighbouring Latvia, Estonia and Poland on building a new plant at the same site.

It is meant to come on stream by 2015, although experts suggest 2017-2020 is more realistic.

In addition, in 2015 Lithuania is due to be hooked up to Sweden's electricity grid via a cable under the Baltic Sea.

Last week, Lithuania's President Valdas Adamkus said he planned to meet with fellow EU leaders to press his country's case.

Prime Minister Gediminas Kirkilas is also due to meet in September with Jose Manuel Barroso, head of the EU's executive European Commission, to try to push for a delay.