The court ordered new elections in 455 - or a fifth - of Berlin's 2256 electoral districts due to irregularities. Parliament had already ordered a repeat in 431 districts but the opposition conservatives wanted a much broader repeat, prompting them to lodge a complaint at the court.

Stefan Marschall, political scientist at the University of Duesseldorf, said the re-run would unlikely impact the majority of Chancellor Olaf Scholz's three-way coalition of centre-left Social Democrats, Greens and business-friendly Free Democrats as it affected few constituencies.

The far-left Linke party could also breathe a sigh of relief, they said, after fearing for its very existence in the parliament in the eventuality of a major electoral re-run.

The party failed in 2021 to reach the 5% hurdle to enter parliament but was able to enter anyway with 39 seats because it secured three direct mandates, two of which were in Berlin. If it lost either of those, it could also lose its proportional representation seats.

Analysts and the party estimated the ordered partial re-run was not in sufficient districts to affect its mandates.

"The consequences will be very manageable," said Thorsten Faas, political scientist at Berlin's Freie Universitaet. "Some mandates will move between parties, but it is virtually excluded that the Linke will lose one of its two Berlin direct mandates."

The September 2021 elections were beset with problems in the capital Berlin, where a shortage of ballots led to long queues and pauses at polling stations, some of which had to stay open late to allow voting.

The city held three elections that day - federal, regional and local - plus a referendum and a city marathon, which added to the chaos due to road closures. COVID-19 restrictions were also still in place at the time.

The constitutional court's decision on Tuesday came around a month after another major ruling that overturned the government's financial plans, contributing to undermining Germany's reputation as a model of efficiency and law and order.

(Reporting by Ursula Knapp, Writing by Rachel More and Sarah Marsh; Editing by Bernadette Baum)