The fall of the conservative government in the state parliament in the state's capital Stuttgart would be regarded as a major blow for Chancellor Angela Merkel's leadership.
The knife-edge poll puts a “black-yellow” coalition of Merkel's conservative Christian Democratic Union (CDU) and the pro-business Free Democratic Party (FDP) at 45 percent of voter support, broadcaster Südwest Rundfunk and daily Stuttgarter Zeitung reported.
This is exactly the same as the combined support for the opposition centre-left Social Democratic Party (SPD) and the environmentalist Greens, according to the poll conducted by Ifratest for the two papers.
The CDU has governed the state since 1953 and a loss of power at the March 27 election would be a serious blow for Merkel's leadership, both practically and symbolically. The large state carries six upper house – or Bundesrat – seats, the loss of which would make it harder for Merkel's black-yellow federal coalition to pass legislation.
But with Merkel's personal popularity in a trough, the loss of so solidly conservative a state would also dent her leadership credibility.
Driving the political change has been the controversial Stuttgart 21 project, a pivotal local issue sparking fiery protests against the massive infrastructure work that have caused problems for CDU state premier Stefan Mappus. However, Merkel has risked some of her own political capital by weighing in on the issue.
If an election were held this Sunday, the CDU would score 39 percent and the FDP six percent. The SPD would win 21 percent of the vote and the Greens 24 percent. The social Left party would score five percent. For a change of government the opposition parties would need 49 percent.
The SPD's leader in the state, Nils Schmid, is just three points behind Mappus as preferred premier, with 36 percent to Mappus' 39 percent, the poll showed. When Greens leader Winfried Kretschmann is pitted against Mappus, he scores 36 percent to Mappus' 43 percent.