The Linkspartei, or Left Party, was inaugurated in mid-July, but an opinion poll yesterday showed that in the former East Germany the organisation had already outstripped Chancellor Gerhard Schröder's ruling Social Democrats and the opposition conservatives.
The poll, published by the Leipziger Volkszeitung newspaper, suggested that the Linkspartei would win 33 per cent of the vote in the east compared to 27 per cent each for the SPD and the conservative Christian democrats headed by Angela Merkel, who remains the favourite to win in September.
The Linkspartei, which came into being earlier this year, is a merger between the successor organisation to the former East German Communist Party and renegade former Social Democrats who recently left Mr Schröder's party in protest against its economic reform programme.
Its election campaign front-runners are the former finance minister "Red" Oskar Lafontaine and Gregor Gysi, a leading member of the former reform Communist Party for Democratic Socialism.
Both men enjoy huge popularity in eastern Germany, where they are viewed as champions of the region's 20 per cent unemployed. They favour a return to "social justice" through higher wages for workers and higher taxes for the rich.
The sudden success of the Linkspartei is causing concern to conservatives and Social Democrats. Officials in Mrs Merkel's party have called for a new political offensive which will underline the conservative leader's East German roots. Mr Schröder has reacted by publicly castigating the new Linkspartei and Mr Lafontaine for his use of far right language at campaign rallies. He has categorically ruled out any future alliance with the organisation.
But the party has already managed to add a new element of unpredictability to the German election. There are fears that if the Linkspartei continues to make such gains, neither of Germany's main parties will win enough votes to secure a comfortable majority.
The upshot could be a coalition of conservatives and Social Democrats. Yesterday's poll suggested only 30 per cent of Germans favoured such an outcome.