President Andrzej Duda was scheduled to take part in a wreath-laying ceremony in the north-central town of Sierpc.
Prime Minister Mateusz Morawiecki was expected to attend an event in the capital Warsaw to honour the fighters, referred to by some as the “Cursed Soldiers” and by others as "Enduring Soldiers."
After Poland's official underground army (AK) of World War II disbanded, thousands of Poles continued to fight in other formations as the Soviet Red Army extended its grip across the country.
The “Cursed Soldiers” faced a brutal crackdown by Poland’s communist authorities and were a taboo subject during the country’s decades under communist rule.
The fighters were largely stamped out by 1948, although one, Józef Franczak, was gunned down as late as 1963.
An official day of remembrance for the fighters was introduced in 2011, more than two decades after the fall of the Iron Curtain.
March 1 was selected as a poignant date for the day of remembrance, as on this day in 1951, seven prominent members of a postwar resistance force called Freedom and Independence were executed in Warsaw.
(gs)
Source: IAR, PAP