WITTENBERG, Germany- The eastern German state of Saxony-Anhalt voted on Sunday in the last test of public opinion before September's national election, one which could deal a blow to conservative Armin Laschet's hopes of succeeding Chancellor Angela Merkel.

Surveys in the state show a small lead for the Christian Democrats (CDU) of Laschet and Merkel, but the far-right Alternative for Germany (AfD) was running just one percentage point behind in the final poll published on Friday.

Casting his vote, conservative state premier Reiner Haseloff said he had done all he could to persuade voters in the relatively poor region not to turn to the far right.

"I've done everything necessary and possible to persuade people that we need stability and a democratic centre," he told reporters in his home town of Wittenberg, where in 1517 Martin Luther nailed his 95 theses critical of the Pope to a church door, igniting the Protestant Reformation.

Turnout, down 8 percentage points on five years ago by 2 p.m., suggested that voters may have chosen not to heed his message. Low turnout has often favoured parties at the political margins.

Though most polls give the CDU a more comfortable lead, a loss or a tight margin of victory could deal a crippling blow to the centrist Laschet's electoral hopes, emboldening those on his party's right who want a decisive break from the Merkel years.

Merkel, in power since 2005, is stepping down after the federal election, and senior CDU officials concede that it will be tough to retain their party's appeal to voters after 16 years in charge. 

National polls show the surging Greens almost tied with the CDU, with both holding around a quarter of the vote, lending the poll in Saxony-Anhalt, a sparsely populated state of just 2.2 million, an outsized significance.

The AfD typically performs better in the former communist east, where the economy is weaker than in the west. Its strength in Saxony-Anhalt has already focused debate on the CDU's relations with the political right.

(Reporting by Reuters TV and Thomas Escritt; Editing by David Evans, Nick Macfie and Jan Harvey) ((thomas.escritt@thomsonreuters.com; +49 30 2888 5217;))