(Adds more on complaint)
BRUSSELS, July 29 (Reuters) - The European Commission launched legal action on Saturday against what it sees as Polish government attempts to undermine the independence of judges.
It gave Warsaw a month to respond.
EU commissioners decided to launch the "infringement procedure" for violating European Union law at a meeting on Wednesday, the first step in a legal process that may end at the bloc's top court, pending publication of Poland's new law.
The Commission is concerned about discretionary power given to Poland's minister of justice to prolong the mandates of judges who reach retirement age, as well as to dismiss and appoint court presidents.
"The new rules allow the minister of justice to exert influence on individual ordinary judges through, in particular, the vague criteria for the prolongation of their mandates thereby undermining the principle of irremovability of judges," the European Commission said in a statement on Saturday.
It said a key legal concern was the introduction of different retirement ages for female judges (60) and male judges (65).
Polish President Andrzej Duda on Tuesday signed into law the bill on ordinary courts, but, in a move welcomed by Brussels, blocked two other bills that would have empowered the government and parliament to replace Supreme Court judges.
Poland's eurosceptic, nationalist government has rejected Brussels' objections as "blackmail" and unjustified criticism, but has said Warsaw was open to talks to resolve the dispute.
Commission First Vice President Frans Timmermans sent a letter on Friday to Poland's foreign minister reiterating an invitation to him and the justice minister to meet in Brussels to relaunch dialogue.
He said on Wednesday that the Commission could trigger Article 7, a legal process of suspending Poland's EU voting rights, if Warsaw went ahead with plans to undermine the independence of the judiciary and the rule of law.
The European Commission also this week gave Poland a month to respond to concerns for the rule of law raised by the EU executive in an unprecedented process launched last year. (Reporting by Philip Blenkinsop; editing by Jeremy Gaunt)