The lower house, the Sejm, is due to start its proceedings at noon, while the upper house of the country’s bicameral legislature, the Senate, is scheduled to begin its first session at 4 p.m.
Conservative lawmaker Antoni Macierewicz, a former defence minister, has been selected to open the inaugural session of the lower house, while opposition senator Barbara Borys-Damięcka is expected to preside over the first sitting of the new Senate.
Poles elected a new set of 460 MPs and 100 senators when they went to the ballot box last month.
The conservative Law and Justice party, allied with two smaller groupings in a United Right coalition, won Poland's October 13 parliamentary election and secured a second term in power.
It maintained a majority in the 460-seat lower house, but narrowly lost control of the 100-seat upper house.
Law and Justice leader Jarosław Kaczyński said ahead of the elections that his party would bring in a raft of new policies during the first 100 days of its next term in government.