Päivi Laine made the assessment in an interview with public broadcaster Polish Radio on Thursday.
The Finnish ambassador said Russia was channeling migrants over the border with Finland, as part of "hybrid attacks against NATO's eastern flank."
Last month, the government in Helsinki closed all land border checkpoints with Russia until January 14, due to an influx of asylum seekers.
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.
Laine told Polish Radio Russia was creating the migrant crisis in retaliation for Finland's entry to NATO.
She added the government in Helsinki had decided to build a wall in "strategic sections of the border," to stem the inflow of asylum seekers from Russia.
The Finnish ambassador said Finland and its people were "ready for any measures that may be taken by Russia," Polish Radio's IAR news agency reported.
Laine added that Finland was seeking to bolster national security through membership of NATO as well as through bilateral defence cooperation with the United States, "similarly to Poland."
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.
Friday is day 681 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: IAR, Reuters, gazeta.pl
