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 election frontrunner Friedrich Merz succeeded on Wednesday in getting a motion passed in parliament that calls for a migration crackdown including the rejection of asylum seekers at the country's land borders.

Germany’s parliament has narrowly approved a call by Chancellor Olaf Scholz’s main challenger to turn back many more migrants at the country’s borders, with the help of a far-right party.

The German Bundestag passed Friedrich Merz's so-called five-point migration plan — which promised a dramatic tightening of the country's migration and asylum law — through parliament. MPs narrowly voted in favour of turning away asylum seekers and other migrants back at Germany's borders — despite criticism that this could break both German and EU asylum law.

Friedrich Merz leaned the right-wing AfD party to push through measures to restrict immigration.

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.