Electricity supplies from Russia to Finland were cut on Saturday after power chiefs carried out their threat to stop the flow.
RAO Nordic, the company responsible for sales of Russian electricity to Finland, said on Friday it would end sales at midnight because of unpaid bills.
The move came as Finnish politicians announced their plan to join the international defence group NATO.
Bosses of Fingrid, the Finnish electricity network, say the country can cope without imports of electricity from Russia. Just under 10 percent off the electricity consumed in Finland comes from Russia.
“The lack of electricity import from Russia will be compensated by importing more electricity from Sweden and by generating more electricity in Finland,” said Reima Päivinen, senior vice-president of power system operations at Fingrid.
A Fingrid spokesperson added: "Finland’s self-sufficiency in electricity generation is constantly improving. In particular, the amount of Finnish wind power generation is increasing every year and Finland is expected to become self-sufficient in electrical energy in 2023."
Tensions
Tensions has been rising between the Finnish and Russian governments since the Russian president Vladimir Putin ordered his country's forces into Ukraine on 24 February.
Sweden is also expected to put forward an application to join NATO. The ruling Social Democrats are due to make a decision on Sunday.
Russia has warned of military and political repercussions if the countries proceed.
NATO Secretary-General Jens Stoltenberg has said the military alliance would welcome Finland and Sweden and said it would be possible to allow them to join quite quickly.
However, the manoeuvring has brought a strong response from Russia.
The the state-run RIA news agency quoted deputy foreign minister Alexander Grushko warning that Russia will act if NATO deploys nuclear forces and infrastructure closer to its border.
Grushko said his country harboured no hostile intentions towards Finland and Sweden adding that he could not see any real reasons for the nations to join NATO.
Interfax quoted Grushko as saying: "It will be necessary to respond ... by taking adequate precautionary measures that would ensure the viability of deterrence."
As the Scandinavians weighed up the pros and cons of NATO membership, foreign ministers from the G7 nations emerged from three days of talks in Germany to reaffirm their backing for Ukraine.
"We will never recognise borders Russia has attempted to change by military aggression," said a joint statement.
"We will uphold our engagement in the support of the sovereignty and territorial integrity of Ukraine, including Crimea, and all states."
