The poll conducted for ARD public television and released Thursday showed Merkel's conservative Christian Union alliance with 42 percent support and her favored coalition partner, the liberal Free Democrats (FDP), with six percent, a decline of one point compared to last week.

With 48 percent support they would fall just below the level needed to win a majority of seats in the parliament.

With six weeks to go before the election, Chancellor Gerhard Schröder's Social Democrats gained a point to reach 29 percent, with their junior partner the Greens at eight percent. A new breakaway alliance, the Left Party, fell one point to 11 percent.

If the results were repeated on election day, September 18, it would make a grand coalition of the Christian Union and Social Democrats the most likely governing alliance. The same poll, conducted by independent research institute Infratest-dimap, found that 39 percent favored a grand coalition at the helm of the next government.

Only 29 percent said they preferred Merkel's choice of the conservatives and liberals and a dismal 14 percent said they wanted to see a continuation of the current ruling coalition of Social Democrats and Greens.

Ten percent backed a coalition of Social Democrats, Greens and the Left Party -- an option Schröder has repeatedly ruled out.

Germany's chronic unemployment has been the main focus of the election but discontent over the tough economic reforms proposed by both the main parties has led to a surge in support for the Left Party under former SPD leader Oskar Lafontaine.

However with six weeks to go before the election and many voters still believed to be undecided, there is still ample scope for the polls to change.