Kaczyński also said that under its new conservative PiS government, Poland needed to “establish the truth” about the reasons for the crash in western Russia.
His comments came in a speech to a crowd of supporters in the culmination of a day of ceremonies across Poland to mark the sixth anniversary of the disaster, in which Kaczyński’s twin brother, former president Lech Kaczyński, was killed along with 95 others.
Jarosław Kaczyński, whose PiS party won a landslide election victory in October, claimed that the previous government led by Donald Tusk, of the centrist Civic Platform party, had tried to “kill remembrance” of the disaster victims.
"Because somebody's responsible for that tragedy, at least morally, irrespective of what its causes were. It's the previous government that was responsible," he said, without elaborating further.
The PiS leader added: “Here on this street, on Krakowskie Przedmieście, a Smolensk monument must arise. On this street there must stand a monument to President Lech Kaczyński.
“Enough waiting. I want to announce from this site that in the next few weeks we will appoint of committee for building these monuments.”
The issue of a monument to those who died in the Smolensk crash is a controversial one. The Warsaw city authorities want a different location, in a less prominent position.
Referring to the crash, Jarosław Kaczyński also said: “We have to establish the truth and we have to draw out all the consequences.”
He added: “Yes, forgiveness is needed. But forgiveness after the admission of guilt and after appropriate punishment is meted out.”
President Andrzej Duda said during commemorations earlier on Sunday that the crash victims deserved "an honest and calm, solid inquiry into what happened.”
Polish Defence Minister Antoni Macierewicz in February appointed a new team of investigators to look into the disaster.
While still an opposition MP, Macierewicz had led the so-called Macierewicz Commission, a group of parliamentarians mainly from the then-opposition Law and Justice party which concluded in a 2014 report that the Polish president's Tupolev 154 plane was brought down by an explosion.
That was in stark contrast to earlier official Polish and Russian reports on the causes of the tragedy, which happened in dense fog on approach to a military airfield lacking ground identification radar.
The former report cited a catalogue of errors on the Polish side, while also pointing to errors made by Russian staff at the control tower of Smolensk Military Airport. The Russian report placed all the blame on the Poles. (pk)