BERLIN: Germany’s centre-left opposition beat Chancellor Angela Merkel’s ruling alliance on Sunday in a cliff-hanger state poll eight months ahead of a national vote, estimates on public television showed.

In one of the tightest German state races in recent memory, the Social Democrats together with the Greens eked out a one-seat lead in Lower Saxony, just ahead of the incumbent coalition of Merkel’s Christian Democrats with the Free Democrats, broadcasters ARD and ZDF said.

After a suspense-packed night with broad implications for the September general election and Merkel's bid for a third four-year term, the centre-left camp said it aimed to use its victory to create fresh momentum.

“It shows the race until September is far from over,” the Social Democrats’ embattled challenger to Merkel, Peer Steinbrueck, told reporters as the results came in.

Merkel enjoys a robust lead in national polls thanks to her fierce defence of German interests in the eurozone crisis.

But pundits said the state poll could help shore up the battered campaign of her gaffe-prone challenger Steinbrueck.

Merkel’s Christian Democrats (CDU) were the strongest party with around 36 per cent of the vote, according to the estimates, which were still pending official confirmation.Their candidate, state premier David McAllister, a half-Scot widely seen as a potential Merkel successor, had held out hope down to the last, calling it a “heart-stopping night”.

Their coalition partners for the last decade in Lower Saxony, the pro-business Free Democrats (FDP), drew nearly 10 per cent — more than doubling many pollsters' expectations and tallying their best result in the state in post-war history.

But their cumulative result fell just short of the Social Democrats' (SPD) around 33 per cent and the Greens' 14 per cent, meaning the opposition can build a governing majority in Germany's fourth most populous state.

Polls had indicated the FDP risked slipping below the five-per cent hurdle required for seats in the state parliament, but it got a lift from conservative voters splitting their ballots under Germany's two-vote system in a bid to rescue the coalition.

ARD television said around 101,000 voters who cast ballots for the conservatives in 2008 had plumped for the FDP this time.

If the FDP failed to win representation, its embattled leader Philipp Roesler, who is also Merkel’s vice chancellor and who hails from Lower Saxony, was seen as likely to step down — possibly as soon as Sunday night.

The outcome seemed to give him a reprieve, if perhaps only brief.

“It is a great day for the FDP in Lower Saxony but it is also a great day for the FDP and liberals in Germany as a whole,” a beaming Roesler told reporters in Berlin.

Around 6.2 million people were called to the polls in Lower Saxony, a northwestern state home to European auto giant Volkswagen.

Steinbrueck, a former finance minister from Merkel's 2005-09 “grand coalition” government, was anointed by the SPD as its chancellor candidate late last year.

But he has run into trouble of late with revelations that he made around 1.25 million euros ($1.66 million) over the last three years in speaking fees, and with comments that Merkel owed much of her popularity to her gender.

The SPD’s candidate in Lower Saxony, Stephan Weil, hinted that he had been forced to campaign in the face of headwinds out of Berlin.

“The SPD made gains, which is remarkable considering the not exactly easy conditions under which we fought for voters' support in recent weeks,” he said.

After Lower Saxony, only the southern state of Bavaria is expected to vote before the September general election.—AFP