The Social Democrats, Greens and Left Party scored a combined total of 49.7 percent in a survey compiled by pollster Synovate and published by newspaper Dagens Nyheter.
The four parties that make up the Alliance government earned the support of 45 percent of the 1,513 people interviewed for the poll, which was carried out from August 17-26.
The Pirate Party, which received over 7 percent of the vote in the recent European Parliament election, fared considerably worse in the Synovate poll and would receive the support of less than 1.5 percent of the electorate were a general election to be held today.
The far-right Sweden Democrats, a party that has climbed above the 4 percent parliamentary threshold in a number of recent polls, receive 3.2 percent in Synovates survey, compared to 3.3 percent in June.
Results of Synovate poll (June results in parentheses):
Moderate Party 26.7 (-1.4)
Liberal Party 8.4 (+0.6)
Centre Party 5.5 (+0.1)
Christian Democrats 4.4 (+0.4)
Social Democrats 36.3 (+2.3)
Left Party 5.3 (-0.1)
Green Party 8.1 (+0.1)
Sweden Democrats 3.2 (-0.1)
Others 2.1 (-2.0)