On Monday, Andrzej Duda, the Polish president, signed into law a bill allowing for the establishment of the investigative body.
Poland goes to the polls this autumn, and opponents of the government argue that the commission could target leading opposition figures such as Donald Tusk, a former prime minister and now leader of Civic Platform (PO), the largest opposition party, ahead of the general election.
"We have a special concern now about the situation in Poland, with the creation by law of a special committee able to deprive citizens, individuals of their right to be elected to a public function, a public office," Reynders said before an EU meeting on Tuesday. "So it will be possible to do that with an administrative decision without any judicial review."
Similar concerns have already been raised by the US State Department and the US ambassador to Poland.
"So it's a special concern and the (European - PAP) Commission will analyse the legislation but we'll not hesitate to take measures if it's needed because it's impossible to agree to such a system without a real access to justice, to an independent judge against an administrative decision," Reynders added.
The commission will have the power to waive an administrative decision it deems was made under Russian influence, and in the case of people who made such decisions issue a ban of up to 10 years from holding a public office that involves public funds.
It will also be able to block their security clearance for up to 10 years.
Government officials have rejected the concerns that the new body could be used for political means, saying its sole aim is to investigate Russian influence on Polish politics. (PAP)