The security meeting, convened by Prime Minister Donald Tusk, began at around 11 a.m., public broadcaster Polish Radio’s IAR news agency reported.
Those taking part included Interior Minister Marcin Kierwiński, Defence Minister Władysław Kosiniak-Kamysz, Foreign Minister Radosław Sikorski, and the minister in charge of the country's secret services, Tomasz Siemoniak.
Jacek Siewiera, who heads President Andrzej Duda's National Security Bureau (BBN), and the heads of Poland's security agencies were also in attendance, alongside the chairman of the parliamentary committee on secret services, broadcaster TVP Info reported.
Tusk said on the X social media platform on Tuesday that the Security Services Council meeting would discuss "alleged Russian and Belarusian influence in the Polish power apparatus in previous years."
Earlier this week, authorities in Warsaw launched a spy probe after a Polish judge asked for political asylum in neighbouring Belarus.
Tusk told reporters on Tuesday that the judge, Tomasz Szmydt, "had access to various classified documents" and ties to Belarus.
"We must be aware that security services, in this case Belarusian ones, worked with a person who had direct access to the Minister of Justice ... who had access to various classified documents to which no intelligence service should have had access," Tusk said before a government meeting in the southern Polish city of Katowice on Tuesday.
He added: "The fact that judge Szmydt's relationship with Belarusians has a long history, that it is not a matter of recent months, must be a cause for deep concern."
Poland, a hub for Western military supplies to Ukraine amid Russia's invasion, is on heightened alert for any signs of spying activity, the Reuters news agency has reported.
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Source: IAR, PAP, Reuters, polskieradio24.pl, TVP Info