The government's statement came in response to a proposal by the World Wide Fund for Nature's Finnish branch to amend Fortum's articles of association at its annual general meeting on Tuesday.
The WWF hopes to pressure Germany's Uniper [UN01.DE], in which Fortum holds a majority stake, to get rid of coal as an energy source.
Earlier this month, Fortum said a final obstacle had been removed for it to gain control of its German rival, ending a more than two-year takeover battle. [L8N2B65J7]
The minister in charge of the Finnish government's ownership steering group, Tytti Tuppurainen, rejected WWF Finland's proposal to include the Paris climate deal's goal of maximum 1.5 degree Celsius temperature rise in Fortum's articles of association.
Such a non-profit move was not possible for a listed company under current legislation, Tuppurainen said. She added, however, that the government wants carbon neutrality to be a joint goal for it and Fortum.
"The (WWF) proposal's ambition is in line with that of the state owner," Tuppurainen wrote.
Environmental organizations including the WWF have criticized Uniper for its decision to proceed with the planned startup of a brand new coal plant, Datteln4 in Germany, despite its effort to cut carbon emissions.
"Fortum should announce a timetable for the shutdown of German energy group Uniper's coal power," WWF Finland wrote in a statement earlier.
Fortum has been careful not to criticize Uniper publicly for its emission cut goals but has demanded strategic alignment, calling Uniper's new strategy to shift towards greener generation "a step in the right direction".
But the Finnish government, which has set carbon neutrality by 2035 as a goal for Finland, may want Fortum to force Uniper to do more.
"The owner supports Fortum's strategy which is built on the assumption that the company will thrive in a carbon neutral society," Tuppurainen said. "We demand a strong execution of the strategy."
(Reporting by Anne Kauranen; Editing by Jan Harvey)