The Finnish government on Thursday afternoon said that all eight checkpoints on the eastern border with Russia will remain closed until 14 April.
The previous decision to extend the closure of the eastern frontier, announced in early January, had been due to elapse on Sunday 11 February.
In a press statement, the government called the move a "necessary and proportionate measure" taken to ensure Finland's "national security and public order".
"Based on the information provided by the authorities, it is likely that instrumentalised migration would resume if border crossing points were opened at the eastern border," the statement said.
Interior Minister Mari Rantanen (Finns) noted Finland has seen "no signs that Russia is changing its behaviour".
"On the contrary, the information we have received confirms our assessment that Russia is continuing its hybrid operation," Rantanen said, adding that "hundreds if not thousands of migrants" may be on the Russian side of the border waiting to cross into Finland.
Russian ambassador: Finnish-Russian relations "completely destroyed"
Russia's ambassador to Finland, Pavel Kuznetsov, said in an interview with the Russian state news agency Ria that relations between the two nations have been "completely destroyed".
"Helsinki's politics have led to a catastrophic collapse of all bilateral cooperation," Kuznetsov said.
He further noted that, based on the rhetoric of the candidates in Finland's presidential election campaign and the overall atmosphere in Finland, relations showed little signs of improving.
His comments come in the wake of similar statements by Russian foreign ministry spokesperson Maria Zakharova on Wednesday.
She accused the Finnish government of "not wanting to discuss with Moscow the threat allegedly posed to Finland from across the Russian border".
"Helsinki stubbornly refuses to discuss with us the threats allegedly posed to Finland's security from Russia's side of the border", Zakharova told Ria Novosti.
In the Finnish government's press release on Thursday, Minister Rantanen noted that "the temporary closure of border crossing points is the result of Russia's actions, which require Finland to put national security first."