The main opposition conservative Law and Justice (PiS) will send a constructive motion of no confidence in Donald Tusk’s government to the Sejm lower house early this month and expects it will be debated on February 20-22, PiS parliamentary caucus spokesman Mariusz Blaszczak said on Thursday.

In line with Poland's constitution, a motion for a constructive no-confidence vote requires presenting a candidate for the post of Prime Minister. The motion has to be signed by at least 46 MPs.

PiS had earlier proposed a non-partisan candidate – an independent sociology professor Piotr Glinski to replace Tusk and form an extra-party cabinet. Glinski will start consultations with parliamentary parties on the composition of his cabinet shortly after PiS tables its no-confidence motion.

Glinski had named a number of priorities he would like to tackle as the Polish PM, including limiting red tape for entrepreneurs and innovative businesses, establishing a non-partisan civil service corps, enhancing the civil society, introducing a broad program of family support, a pro-development spending of EU funds as well as enhancing homeland security.

According to PiS leader Jaroslaw Kaczynski a non-parliamentary government would be best for Poland in its present situation. "No social problems are being tackled. Unemployment is on the rise, Poles are leaving their country and our public finances are in crisis", Kaczynski said of Tusk's government.

PiS must secure an absolute majority of 231 votes and the sympathy of the left-wing opposition and a rightist splinter party Solidary Poland which is sporting a PM candidate of its own.