"Finland's decision to initiate NATO accession is great news for Poland and Europe's security," Mateusz Morawiecki said in a tweet.
"Poland supports Finland joining NATO as quickly and smoothly as possible," he added.
Finland's President Sauli Niinisto and Prime Minister Sanna Marin said in a joint statement on Thursday that their country "must apply for NATO membership without delay."
They added: "We hope that the national steps still needed to make this decision will be taken rapidly within the next few days."
Finland, which borders Russia to the east, deepened its ties with the 30-member Western military alliance after Moscow annexed the Crimea peninsula from Ukraine in 2014, Polish private broadcaster Polsat News reported.
But it said the country has so far refrained from joining not to antagonize its giant neighbour.
Finland is expected to formally announce its decision on Sunday after it has been considered by parliament and other senior political figures, British broadcaster BBC reported.
Meanwhile, Swedish Foreign Minister Ann Linde said on Thursday that her country would take into account
Finland's NATO assessments when making its own decision on whether it should seek to join the Atlantic military alliance, the Reuters news agency reported.
"Finland is Sweden's closest security and defence partner, and we need to take Finland's assessments into account," Linde said on Twitter.
She added that Sweden "will decide" after a report from "security policy consultations has been presented."
(gs)
Source: IAR, PAP, polsatnews.pl, bbc.com, Reuters