Former German Chancellor Angela Merkel has issued rare public criticism of her successor as the country’s center-right leader, the front-runner in Germany’s election next month, for putting to parliament proposals for tough new migration rules that only passed with the help of a far-right party.

German conservative leader Friedrich Merz on Wednesday defended his controversial migration reforms after stinging criticism from Chancellor Olaf Scholz, ahead of votes on two motions that could pass with the support of the far-right Alternative for Germany (AfD).

Chancellor Olaf Scholz's main challenger in Germany's upcoming election plans to put proposals for a tougher migration policy to parliament on Wednesday, a maneuver aimed at piling pressure on the governing parties that has brought accusations that he's breaking commitments to shun the far right.

With less than four weeks before Germany’s federal election, Chancellor Olaf Scholz and his conservative challenger Friedrich Merz, who is leading polls, will take their contentious battle over how to crack down on illegal migration to parliament.

The CDU party chief, who leads in the polls to become the next chancellor, said he would collect votes from all parties to push his five-point migration plan through parliament despite Chancellor Olaf Scholz's strong opposition.