HELSINKI, Jan 27 (Reuters) - Electricity production at Finland's much delayed Olkiluoto 3 nuclear reactor has been pushed back by a day to Feb. 1, operator Teollisuuden Voima (TVO) said in a statement late on Wednesday.

TVO has been pushing back the electricity production start date, once slated for Jan. 22, since an automatic trip shut down test production on Jan. 14.

Currently the reactor is estimated to operate at 25% of its total capacity when it is connected to the grid at the beginning of February, and reach total capacity of 1.6 gigawatts in June.

TVO's Olkiluoto 3, a joint venture of Finnish utility Fortum and a consortium of smaller energy and forestry companies, will be Finland's first new nuclear facility in four decades.

It was meant to be finished in 2009 but the project has been beset by technological setbacks that drove TVO and its partners, France's Areva and Germany's Siemens, into a lengthy legal battle https://www.reuters.com/article/us-tvo-areva-olkiluoto-settlement-idUSKCN1GN0R5 over compensation. (Reporting by Essi Lehto; Editing by Jan Harvey)