The interior ministry in Helsinki announced the move on Thursday, Poland's state broadcaster Belsat reported.
Finland closed all land checkpoints on the border with Russia late last year, until January 14.
The Finnish government said it was a response to a growing influx of migrants channeled over the border by Russia, the Reuters news agency reported.
Around 900 migrants from nations such as Kenya, Morocco, Pakistan, Somalia, Syria and Yemen entered Finland from Russia in November, according to officials.
Previously the average number of crossings was less than one per day, Finland's Border Guard agency said.
"Based on the information gathered by the authorities, the threat of the phenomenon restarting and expanding as previously experienced is likely", the interior ministry in Helsinki said on Thursday, as it announced an extension of the border closure until February 11.
Finland became NATO's newest member in April 2023, following Russia's February 2022 invasion of Ukraine.
On December 18, Finland signed a defence agreement with the United States, giving US forces broad access to the vicinity of the 1,300 km Finnish-Russian border, according to news outlets.
Thursday is day 687 of Russia’s war on Ukraine.
Russia invaded Ukraine on February 24, 2022, launching the largest military campaign in Europe since World War II.
Source: Belsat, Reuters, YLE
