In April, the technical arm of nuclear regulator ASN recommended EDF repair some of the reactor's faulty weldings, which could cost hundreds of millions of euros. The ASN is expected to rule on the weldings in June.

"We will see delays due to the redoing of the weldings," Levy said at a debate organised by financial daily Les Echos.

Levy did not make clear whether the ASN had given EDF any indication about its upcoming decision, but a company official told Reuters that EDF had not been informed.

The Flamanville project is already years behind schedule and billions over budget.

"If we did not have to redo the weldings... the Flamanville project would be finalised," Levy said.

Following the discovery of the problems with the weldings, EDF in July 2018 delayed the scheduled loading of nuclear fuel by a year to the fourth quarter of 2019.

(Reporting by Benjamin Mallet; Writing by Geert De Clercq. Editing by Jane Merriman)