The poll shows that only 1.2 percentage points separates the blocs – 47.8 percent to 46.6 percent.
The Moderate party is the main loser in the poll, falling a statistically significant 3.8 percentage points to 29.3 percent since the previous Synovate poll in June. The Social Democrats reclaimed their place largest party with 31.3 percent, still way below their result in the 2006 election.
The Moderates have lost some of their support to other centre-right partner parties, who all saw gains in support. The Liberal Party (Folkpartiet) polled 7.4 percent, the Christian Democrats 5.9 percent, and the Centre Party 5.1 percent.
The number of undecided voters has increased to 22.2 percent of the electorate, with every tenth person who voted for the Alliance in the last election uncertain of how to cast their vote.
The Green Party could lay claim to 10.8 percent, their highest figure since 2006, while the Left Party continued to struggle, polling 4.4 percent in the Synovate survey.
The poll also shows that the destiny of the far-right Sweden Democrats remains too close to call, with the party on 3.6 percent – below the threshold for parliamentary seats.