The party, one of the major success stories at the September general election, fell back 2.6 percentage points to poll 7.7 percent in Sifo's voter barometer for February, published in the Svenska Dagbladet (SvD) daily on Sunday.
"Some Green Party voters have probably gone to the Social Democrats and some into the uncertain category. Over the past month the party has been invisible in the debate and they are also about to change spokespersons," said Toivo Sjörén at Sifo to SvD.
The Social Democrats increased by 2.4 percentage points to 30.2 percent, but the change is not statistically significant. For other parties, the changes are small.
Alliance parties get together 49.3 percent and the Red-Green 43.3. Alliance lead shrinks thus from 7.7 percentage points to 6.
For the remainder of the parties in Sweden, the polls reflected few changes with the the Sweden Democrats falling back 0.5 percent and the Christian Democrats and Centre parties remaining below their election results.
Sifo poll results, February 2011 (changes from January 2011 in parentheses)
Moderate Party 33.4 (-0.5)
Centre Party 5.1 (+0.4)
Liberal Party 6.5 (-0.6)
Christian Democrats 4.3 (-0.1)
Total: 51.7 (Election 2006: 48.2)
Social Democrats 30.2 (+2.4)
Left Party 5.4 (+1.1)
Green Party 7.7 (-2.6)
Total: 42.0 (Election 2006: 46.1)
Sweden Democrats 6.4 (-0.5)
Others 1.2 (+0.6)
Sifo asked 1917 people which party they would vote for if the election were held today. Interviews were conducted on February 7th to 17th.