BERLIN (Reuters) - Two in three members of Germany's Social Democrats (SPD) oppose joining a 'grand coalition' with Angela Merkel's conservatives, according to a poll on Friday that underlined the dilemma facing the centre-left opposition party.
The poll was published hours before SPD representatives were due to meet in Berlin to decide whether to start coalition talks with Merkel after she won last Sunday's national election but remained short of a majority and in need of a coalition partner.
There is strong public support for a right-left coalition but Social Democrats are split on the issue, recalling how their party lost millions of votes after teaming up with Merkel in her first term from 2005 to 2009.
The Forsa poll showed 65 percent of SPD members do not want their party to enter an alliance with the conservatives. Some 70 percent of party officials said they were not in favor.
By contrast, more than half of Germans who voted for the SPD in the election said they would welcome a 'grand coalition' and only 40 percent of them were against it, the survey showed.
"Once again the SPD faces a discrepancy between its voters, potential voters and party activists," said Manfred Guellner, head of the Forsa polling institute.
"If it follows the opinion of its members, the concerns many voters harbor about the SPD will strengthen further."
The SPD, which has about 470,000 card-carrying members, suffered its second-worst postwar performance in last Sunday's election but will remain the biggest party in parliament after Merkel's conservative bloc.
Those on the left of the party want all party members to be allowed to vote on any decision to join a grand coalition, an unwieldy and unpredictable process.
Merkel had wanted to continue in power with her outgoing coalition partner, the business-friendly Free Democrats (FDP), but they failed to clear the 5 percent threshold to enter the Bundestag lower house of parliament.
Of the three other parties represented in the new Bundestag, the SPD is regarded as her most likely new coalition partner, despite its members' reluctance. The other parties are the environmentalist Greens and the hardline Left.
Forsa conducted its survey on September 25-26. Of the 1,001 participants, 174 voted for the SPD in Sunday's election and 926 are members of the party.
(Reporting by Michelle Martin, editing by Gareth Jones)