OSLO, Feb 22 (Reuters) - Norway's $1.3 trillion wealth fund on Wednesday put Polish energy group PKN Orlen under observation for a period of three years, citing "unacceptable risk that the company contributes to serious violations of human rights".

"This recommendation rests on Orlen's acquisition of the newspaper publisher Polska Press and its implications for freedom of the press and therefore freedom of expression in Poland," the Fund's Council of Ethics said in a statement. (Reporting by Victoria Klesty, writing by Nerijus Adomaitis, editing by Sandra Maler)