Gasum also confirmed on Saturday that the flows has stopped.
"Natural gas supplies to Finland under Gasum's supply contract have been cut off," it said in a statement.
"Starting from today, during the upcoming summer season, Gasum will supply natural gas to its customers from other sources through the Balticconnector pipeline." Balticconnector links Finland to neighbouring Estonia's gas grid.
The majority of gas used in Finland comes from Russia but gas only accounts for about 5% of its annual energy consumption.
Most European supply contracts are denominated in euros or dollars and Moscow already cut off gas to Bulgaria and Poland last month after they refused to comply with the new payment terms.