German Chancellor Angela Merkel speaks at the opening of a new research center for dementia diseases DZNE at the university hospital in Bonn, Germany, March 15, 2017. REUTERS/Wolfgang Rattay

BERLIN (Reuters) - Angela Merkel’s conservatives have a slight lead over the Social Democrats (SPD) but a left-leaning alliance led by the SPD would have enough support to wrest power from the German chancellor, a poll showed six months before a federal election.

The conservatives were unchanged on 33 percent while the SPD dropped one percentage point from last week to 32 percent, the Emnid poll for Bild am Sonntag newspaper showed.

Support for the far-left Linke was steady at 8 percent while support for the Greens rose by one point to 8 percent. That would give a “red-red-green” alliance of the SPD, Linke and Greens 48 percent - which the newspaper said would be enough to form a coalition government.

The SPD trailed the conservatives in opinion polls for years but its support has surged since late January, when it nominated former European Parliament President Martin Schulz as its challenger to Merkel in a Sept. 24 election - a move that also resulted in a sharp increase in SPD members.

Schulz is campaigning on issues such as social justice and suggesting revisions to Agenda 2010 labor market reforms rolled out by Gerhard Schroeder, the last SPD chancellor.

Merkel’s conservatives have been in power since 2005, forming a coalition with the SPD in their first term as well as the current legislative period. In between, the conservatives teamed up with the pro-business Free Democrats (FDP) until they crashed out of parliament in 2013.

In a direct vote for the chancellor, 46 percent would choose Merkel while 38 percent would pick Schulz, the poll showed. In early February, Schulz would have won such a popularity contest with 46 percent and Merkel on 40 percent.

The Emnid poll showed the right-wing Alternative for Germany (AfD) gaining one percentage point to reach 9 percent while the FDP dropped one point but was still at the 5 percent threshold necessary to enter the lower house of parliament.

Emnid asked 1,832 people about their party preferences between March 9 and March 15. It polled 501 people on March 16 on the direct vote for chancellor question.