Finland's much-delayed EPR nuclear reactor is to begin testing in February next year, French atomic energy giant Areva and its Finnish counterpart TVO announced Friday.

Areva, together with German engineering group Siemens, is building a European Pressurised Reactor (EPR) -- a new, third-generation reactor design considered one of the most advanced in the world -- at the Olkiluoto plant in western Finland.

"Installation (of the instrumentation and control cabinets) will enable the plant's systems commissioning to begin in the first quarter of 2016," Areva's project director Jean-Pierre Mouroux said in a joint statement from the two companies.

Originally scheduled to start operations in 2009, recurrent delays have plagued the project since the beginning, following a series of technical and safety setbacks.

The cost of the reactor has run far over budget and has landed Areva and TVO in a several billion-euro dispute in a Paris arbitration court.

The two project heads refused to speak of reconciliation on Friday but Mouroux told AFP: "What happened before, it's gone now. Now we are at the test phase."

"Our cooperation has evolved in a very good manner. We have even partly merged our offices at the site," TVO's project director Jouni Silvennoinen told AFP during a visit to the reactor.

The Olkiluoto 3 reactor, situated on a beautiful cape overlooking the sea, appears complete from the outside but inside some 40,000 wires have yet to be connected, as part of the automation process.

Part of the automation system has been delivered by Areva's German partner Siemens and has been previously tested in Germany.

Finland radiation safety authority STUK approved the tests and the systems are now being installed in Olkiluoto.

The reactor is now expected to start operations in 2018.