Russia's Gazprom has informed Finland that it will halt flows of natural gas from Saturday morning, Finnish state-owned gas wholesaler Gasum said on Friday.
Gasum has refused to pay Gazprom Export in roubles as Russia has requested European countries to do.
"It is highly regrettable that natural gas supplies under our supply contract will now be halted," Gasum CEO Mika Wiljanen said in a statement, reports Reuters.
"However, we have been carefully preparing for this situation and provided that there will be no disruptions in the gas transmission network, we will be able to supply all our customers with gas in the coming months," he said.
The cut-off is scheduled to take place at 0400 GMT on May 21.
Gasum said it will continue to supply gas to Finnish customers from other sources through the Balticconnector pipeline connecting Finland with Estonia.
Gasum had warned on Wednesday that Russia could cut off gas supplies due to the conflict over rouble payments.
The majority of gas used in Finland comes from Russia but gas only accounts for about 5% of its annual energy consumption.
Gazprom did not immediately respond to a request for comment.
Earlier on Friday, prior to the Gasum announcement, Kremlin spokesman Dmitry Peskov said Moscow did not have detailed information regarding Gazprom's supply contracts.
"But obviously nothing will be supplied to anyone for free," Peskov said.
The prospect of losing most of the gas supply has prompted Finnish industry majors like Neste, Metsa and others to seek alternative energy sources or make contingency plans to adapt their production.
Forestry group Stora Enso has said it had already replaced Russian natural gas with liquefied natural gas (LNG) at all its units.
Its peer UPM said it uses gas delivered via the BalticConnector pipeline from Western providers but is nevertheless preparing for the possibility of short-term disruptions.