The BBN's head, Jacek Siewiera, announced the mission in an interview with state broadcaster TVP Info on Tuesday night.
He said that the advisers would "share Poland's experiences" in tackling "a hybrid attack from Belarus" over the past two years, the PAP news agency reported.
Siewiera told TVP Info that efforts to deal with the attack had included "countering information warfare threats," building a steel wall along the border with Belarus to block an orchestrated influx of illegal migrants, and "responding to the violation of Polish airspace by Belarusian helicopters."
He added that Polish advisers would head to Finland at the request of President Sauli Niinistö.
The Finnish president discussed the situation on his country's border with Russia during talks with Polish President Andrzej Duda in Warsaw last week.
Earlier on Tuesday, Finland announced a complete closure of its border with Russia until at least December 13, due to "an influx of migrants from third-party countries" and Moscow's "coordinated actions designed to exert an influence," the PAP news agency reported.
Some 1,000 asylum seekers have crossed the border from Russia to Finland this autumn, according to Finnish media.
Russia invaded Ukraine on February 24, 2022, launching the largest military campaign in Europe since World War II.
Wednesday is day 644 of Russia’s war on Ukraine.
Source: IAR, PAP, TVP Info