Berlin  - Chancellor Angela Merkel's conservative party suffered a stinging setback Sunday in two of three German state assembly elections, with small parties eating into the Christian Democratic Union (CDU) support.

Merkel's federal-level ally, the Social Democratic Party (SPD) took comfort from the CDU's losses and from its own future as an indispensable partner in state coalitions.

But it failed to take up the slack from the CDU as the September 27 national elections loomed. Instead, the notable gains were scored by smaller parties.

In Thuringia, the CDU vote share was projected at 31.3 to 31.7 per cent, sharply down from 43.0 per cent at the last poll.

SPD support in that state gained 5 percentage points to 17.9 per cent, but still trailed both the CDU and the Left (27.9 per cent), the party of the former communists, an ARD projection showed as vote counting continued.

Saarland, the only western state in play, gave the SPD 24.5 per cent of the vote to 34.5 per cent for the CDU, according to the official result - while the Left, a party that was previously seen as a voice of eastern Germans only, won 21.3 per cent.

That was a stunning gain of 19 percentage points since the last Saarland poll.

Saarland, a state of coalmines and steel plants, was formerly SPD heartland. The gains were credited to Oskar Lafontaine, a former SPD state premier who defected to the Left Party in 2005 and is now its co-leader.

In industrialized Saxony, the CDU maintained its support (40.7 per cent). The Left (20.9 per cent) overshadowed the SPD, which again won only 10 per cent, level-pegging with the FDP.

The Free Democrats and Greens were also cheered by local gains in the state polls.

CDU officials appealed to Merkel to perk up her general election campaign. So far the national campaign has been lacklustre, with no sharply delineated issues separating the SPD and CDU.

Merkel, whose national support is rated at 36 per cent, said earlier she did not regard the state polls as a test.

A political surveys institute, Forschungsgruppe Wahlen, agreed, saying local circumstances in the three states had been key factors in the results, with the same voters likely to cast their ballots differently at the end of September.

They said dissatisfaction had grown with Saarland's Mueller and Thuringia's CDU premier, Dieter Althaus, who was fined for manslaughter by negligence after a January 1 ski-field collision in which a woman was killed and he suffered head injuries.

Saxony's CDU premier, Stanislaw Tillich, however, had gained strong personal support in his first year in power. That was reflected in a vote share above 40 per cent, little changed from 41.1 per cent five years ago.

The far-right National Democratic Party (NPD) again gained seats in the Saxony state assembly, winning 5.5 per cent of the vote, but that was a sharp fall from the 12 per cent it won five years ago. (dpa)