Low turnout appears to have scuppered a Bulgarian referendum on whether the former Communist nation should build a second nuclear power plant.

Some 4.35 million people, about 60 percent of eligible voters, needed to cast ballots for the results to be binding.

Although the central electoral committee is yet to announce its final turnout figures, exit polls showed that participation was somewhere between 20.5 and 21.8 percent.

The final turnout figures are expected to be announced on Tuesday.

Central electoral committee spokesman Biser Troyanov told AFP that out of those who did cast ballots, 60.66 percent said "yes" to the poll question: "Should Bulgaria develop nuclear energy by constructing a new nuclear power plant?"

Some 37.93 percent were against and there were 1.4 percent of invalid ballots, Troyanov added, citing an almost total count of the ballots.

If final official participation is confirmed to be over 20 percent, with over half of the voters in the "yes" camp, parliament will have to review the issue within three months.

Lawmakers will not be obliged however to revive the on-again, off-again Belene project which was at stake in the referendum question.

The right-wing government of Prime Minister Boyko Borisov decided last March to ditch a deal with Russian state-owned company Atomstroyexport to build the 2,000-megawatt plant at Belene in northern Bulgaria.

And Borisov confirmed late Sunday that his near-majority GERB party will definitely overthrow the long-delayed project once again.

The government is not against nuclear energy in general.

It already announced plans to extend the operational life of the two reactors at Bulgaria's single nuclear power plant at Kozloduy and to possibly add another reactor at the same site.