Merkel's conservative bloc still seems to be heading to victory in September 22nd's election, but in the latest poll he was up six points and will hope to gain further ground in a live television debate between the two rivals on Sunday.
Steinbrück would get 28 percent of support if the election to chancellor were via direct vote, the latest ARD broadcaster's poll suggested. This is a six-percent increase on his score a couple of weeks ago, but is still way off Merkel's share of 54 percent.
With just over three weeks before voters go to the polls, Merkel still looks to be leading her bloc of Christian Democratic Union (CDU) and Christian Social Union (CSU) to another victory. The ZDF broadcaster's latest poll says the bloc would get 41 percent of the vote, while Steinbrück's SPD languishes on 26 percent.
Merkel's current coalition partner, the business-friendly Free Democrats (FDP) seem set to clear the parliamentary hurdle of five percent, with six, while the SPD's chosen partner, the Greens, are predicted to get 12 percent. The socialist Linke are heading for seven percent.
The figures predict Merkel's coalition would get 47 percent, while the SPD and Greens, even if they were to form a coalition with the Linke, would still be behind on 45 percent.
The ARD-commissioned poll came up with similar numbers, giving Merkel's coalition a slim majority over the other three parties.
"We are registering an extreme loss of trust in both major parties. With the SPD we are talking of a halving of their share of the vote in terms of those allowed to vote, over the last 11 years," said Manfred Güllner, head of Forsa polling firm.
Sunday's televised debate between Steinbrück and Merkel could make a difference, he suggested, noting that the 2005 debate between Merkel and the then SPD chancellor Gerhard Schröder, convinced 2.9 million undecided voters to go for Schröder - boosting the party's performance by 3.7 percent.
But not many Germans expect Steinbrück to be able to turn things around in the debate. The ARD poll suggested that 48 percent of people expected Merkel to come out on top, while just 26 percent thought Steinbrück could win.