Finnish electricity company TVO said on Monday that an EPR nuclear reactor being built by Areva and Siemens may not be ready until 2016, contradicting Areva's claims that it would be completed in 2014.

"Based on the recent progress reports received from the plant supplier ... TVO is preparing for the possibility that the start of the regular electricity production of Olkiluoto 3 nuclear power plant unit may be postponed until the year 2016," the company said in a statement.

In August, TVO said that the reactor being built in southwestern Finland would not be ready to produce electricity in 2014, but declined to give a new completion date.

Areva president Luc Oursel told a Finnish business daily in September that the group was on track to complete the project in 2014.

TVO lacked "an adequate schedule update", but about 75 percent of the installation works had been completed, the Finnish company's project manager, Jouni Silvennoinen, said Monday.

"Although TVO is not pleased with the situation and repeated challenges with the project scheduling, the works are proceeding," he said.

Monday's announcement marked only the latest in a string of setbacks for the construction project, which began in 2005, with the reactor initially supposed to begin producing electricity in 2009.

The Finnish EPR, or European Pressurized Reactor, is an example of so-called third-generation nuclear technology developed by Areva.

It is set to have a capacity of 1,600 megawatts, and was first delayed until November 2010, then to December 2011 and then to August 2014.