European Union lawmakers said on Wednesday they had "deep concern" over Slovakia's planned criminal code changes and shutting a special prosecutor's office, piling on criticism of the government's plan to fast-track the changes, Paralel.Az reports citing Reuters.

The European Parliament, in a resolution approved by 496 of the 630 lawmakers who voted, said the changes needed more scrutiny and called on the European Commission to take action "to safeguard the rule of law and judicial independence".

Prime Minister Robert Fico's leftist, populist government, in power since October, unveiled the legislative changes in December and has faced near-weekly protests led by pro-Western liberal and conservative opposition parties.

The opposition says the reforms would protect allies of the current government from facing prosecution, and would put EU funds at risk if deemed to undermine the rule of law - an issue that has pitted Poland and Hungary against the European Union.

The Commission and the United States have already raised objections to the quick pace of reform after the government said it would put the legislation to Slovakia's parliament in a fast-track procedure.

Slovak President Zuzana Caputova has threatened to veto the legislation, although Fico's government will be able to override her move.

The EU parliament's resolution said the criminal code amendment and the dissolution of the special prosecutor's office (USP) - which has handled major corruption cases for two decades - "threatens the integrity of judicial processes, undermines the European Union's fight against fraud and jeopardises the protection of the EU's financial interests."

The Slovak government's plan also includes limiting protection for whistleblowers and reducing sentences for financial crimes.

The USP opened a number of cases against business leaders, judicial and police officers, some linked to Fico's party, following a 2020 election win by parties promising to weed out graft.

According to Slovak media, 40 people have been sentenced while another 130 are being investigated or tried.

The EU's justice commissioner Didier Reynders said in mid-December the Commission could take action against Slovakia if it enacts criminal law changes that violate EU laws.

Forced to resign after mass protests in 2018 following the murder of anti-corruption journalist Jan Kuciak, Fico returned to power for a fourth time after a September election.

He has accused the USP and its leader Daniel Lipsic, a former justice minister in a non-Fico government, of being politically biased against his SMER-SSD party.