The Cengiz-Kolin-Kalyon (CKK) consortium -- made out of three major privately-owned Turkish industrial conglomerates -- has left the project due to a failure to agree commercial terms, the state run Anadolu news agency said.

Contacted by AFP, Cengiz Holding, one of the companies in the consortium, declined to comment.

A Russian newspaper carried a similar report, saying that the private companies would be replaced by a state-run Turkish energy firm.

Russia's state atomic energy cooperation Rosatom is to build the plant at Akkuyu in the southern Turkish Mediterranean province of Mersin.

Rosatom holds the majority 51 percent stake in the project, with the Turkish consortium 49 percent.

The atomic power station is the first of three already being planned by energy resource-poor Turkey to meet the needs of its growing 80 million population.

Its construction is a major symbol of the current close relations between Ankara and Moscow after a reconciliation deal in summer 2016 ended a bitter half year row over Syria.

Turkish officials expect construction of the plant to begin this year with the facility starting to come online from 2023, the 100th anniversary of the founding of the modern Turkish Republic.

Russian daily RBK quoted two sources close to the project as confirming CKK was leaving the project, adding it would be replaced by state-run Turkish energy firm EUAS.

A Rosatom spokesperson confirmed to the paper that it was continuing to look for investors and "EUAS is one of the companies with whom we are in talks."

RBK said the final agreement between shareholders on the building of the plant was to have been signed in late 2017 but this never happened.

Russian media have said that both sides wanted private Turkish investors to partner Rosatom in the project but its financial demands have meant that this was not possible.