Orsted, formerly named DONG Energy, sold its oil and gas assets in 2017 to focus on offshore wind, but a supply deal signed with Gazprom in 2006 which runs until 2030 remains in place.

Orsted, which is 50.1% owned by the Danish state, said it would continue to buy gas from the Russian state-controlled gas firm despite criticism from Danish lawmakers.

Western allies have tried to isolate Russia economically following Moscow's invasion of Ukraine last week.

"Shortfalls in gas supplies will, as opposed to stopping supply of other types of products, have severe human and societal consequences," Orsted chief executive Mads Nipper said in a statement on Sunday.

"The dependency on Russian gas and any ban on import of gas from Russia need to be decided and enforced by clear political sanctions," Nipper said, urging for "a clear and coordinated effort from the EU and the UK".

Orsted could not legally breach the Gazprom contract, a spokesperson for the Danish company said.

Denmark get roughly 75% of its natural gas through pipelines from Germany and Nipper told Danish daily Berlingske that the vast majority of that is sourced via Orsted's Gazprom contract. Orsted declined to say exactly how much gas it buys from Gazprom.

Orsted also said it had stopped all sourcing of Russian biomass and coal for its power stations, of which only one is coal-fired, and is not entering into new contracts with companies or using suppliers from Russia.

(Reporting by Stine Jacobsen, Editing by Louise Heavens)