Reports from Sofia, Bulgaria, suggest that the long-delayed construction of the country's Belene nuclear plant is set for further holdups as the tenders submitted to build it have disappointed the government.

The Sofia News Agency reports that the financial, technical and timescale details of the plant’s construction from both the firms bidding to build it are unsatisfactory, according to the country’s energy ministry.

The two competing groups are Russia’s Atomstroiexport and the Czech company Skoda Alliance.

It is hoped that the Belene facility will have two functioning reactors by 2018, by which time it will be Bulgaria’s sole nuclear facility. The Belene project was first mooted in 1986, the Bulgarian news agency says.