Marcinkiewicz made the announcement after meeting with Belarusian opposition leader Alyaksandr Milinkevich in the northern Polish city of Bialystok.
Milinkievich, who is Belarus' leading opposition presidential candidate, said the planned radio station was "very important." He said it would supply independent information to his country.
Poland had previously said the broadcasts would include programs in Belarusian and Polish. Western Belarus is home to many ethnic Poles, whose rights Warsaw says are being violated.
Poland has positioned itself as a leading regional opponent to the authoritarian government of Belarusian President Alyaksandr Lukashenka. Marcinkiewicz today said his country was considering sending observers to monitor Belarus's upcoming polls.