(Adds Fortum, details, background)
HELSINKI, June 30 (Reuters) - Finnish consortium Fennovoima has submitted an application to build a nuclear reactor supplied by Russia's state-owned Rosatom, the economy ministry said on Tuesday.
The 6 billion euro ($6.7 billion) plan will strengthen Finland's energy ties with Moscow, which is already the sole external natural gas supplier, despite European Union concerns about energy dependence on Russia.
"Yes (they have submitted the application), and we will update the media shortly," a ministry official told Reuters, declining to comment further.
Finland's Economy Minister Olli Rehn is planning to hold a news conference on the Fennovoima project at 1400 GMT.
The Finnish parliament has set a requirement for the project to be 60 percent owned by Finnish or European Union investors, but the final ownership structure was not immediately clear.
Finnish utility Fortum said last week it has not reached an agreement with its Russian partners to take a 15 percent stake in the project, causing doubts about its fate.
"We are in the same situation as we were last week," Helena Aatinen, Fortum's spokewoman said after the ministry confirmed Fennovoima's application was submitted.
Aatinen, however, declined to say whether Fortum might join the project at a later stage if the talks are successful.
Fennovoima, which has submitted the application about an hour before the official deadline, was not available to comment.
The 1,200-megawatt Hanhiviki-1 reactor, Finland's sixth, is aimed at securing a steady energy supply for its owners including Finnish steelmaker Outokumpu and to be built by 2024.
Germany's E.ON, originally a top investor, left the consortium in 2012, to be replaced by Rosatom. A weak economy and low energy prices have also forced some Finnish investors to reconsider their participation.
Finland generates about 30 percent of electricity from its four nuclear reactors, and the fifth, Olkiluoto-3, is expected to start at the end of 2018.
Russia, which provides around one third of the EU's oil and gas, sent shockwaves through the international community with its annexation of Ukraine's Crimea peninsula in 2014. ($1 = 0.8907 euros) (Reporting by Anna Ercanbrack, writing by Nerijus Adomaitis; Editing by Keith Weir)