Part of the centre-right Alliance bloc, the Centre Party pulled in 5.4 percent of the vote in a similar poll in June.
The Demoskop poll, commissioned by TV4 and in Expressen, showed the Alliance had the support of 51.5 percent of respondents, while the Social Democrats and its left-wing coalition (the Green Party and the Left Party) had 44.2 percent.
The Green Party fell 2.5 percent while the Left Party sunk 2 percent in the poll.
The confidence poll interviewed 1,000 people during July 4 to July 11.
Swedish national elections are September 17.