Kaczynski said at a joint press conference with Mateusz Morawiecki, the prime minister, on Tuesday, that the body would "investigate the energy policy pursued by Poland's government in 2007-2015."
The time span covers the whole two terms of the previous government, which was led by the centrist Civic Platform (PO) party, the main rival of PiS.
The PiS proposal also constitutes a reversal of the idea first put forward by PO in October. The now-opposition party wanted to look into potential Russian involvement in the Polish energy policy between 2013 and 2022 after media reported there could have been Russian links in a high-profile wiretapping scandal.
Kaczynski went on to say that "the issue has become a subject of controversy and it would be useful to explain all the matters connected with it."
Morawiecki said "some people" were trying to "hide their past activities and repaint their image."
"Poles want to know the truth and that's why this commission that will verify Russian influence on Polish internal security is needed, not only to clear up the past, but also to get rid of Russia's residual influence once and for all," the prime minister added.
On October 21, the Civic Coalition (KO), of which PO is the backbone party, filed a motion to set up an investigative commission to check whether public bodies were capable of preventing and counteracting the influence foreign intelligence services had on Poland's energy policy between 2013 and 2022.
The motion came in the wake of a media report that secretly-taped informal conversations of top government politicians in 2014 were first heard by the Russian intelligence services before they made their way to the Polish press.
The publication of the conversations shook the PO-led government. One year later, the party lost power in the 2015 general election to PiS. (PAP)
jd/md/ej