A lawmaker for Germany's Social Democrats (SPD) has called for unity as lawmakers were set to vote in a second secret ballot to elect conservative Friedrich Merz as the country's new chancellor, after a historic defeat in a first round earlier on Tuesday.

German conservative leader Friedrich Merz failed to secure enough parliamentary votes to become chancellor in a major blow.

BERLIN (Reuters) - German conservative leader Friedrich Merz failed to secure enough parliamentary votes to become chancellor on Tuesday, throwing politics in Europe's largest economy into disarray as it seeks to emerge from recession and stem far-right extremism.