Pollsters Synovate asked voters a number of questions on how they perceived the two leaders. Sahlin leads Reinfeldt on a number of key measures, but in other areas voters give the prime minister the edge.
Some 48 percent said Reinfeldt was the more capable of the two to lead a government, with 37 opting for Sahlin. The remainder were undecided.
Reinfeldt was better at representing Sweden abroad, with 55 favouring the prime minister. Only 31 percent rated Sahlin highest on this point.
Sahlin scored highly when voters were asked which of the two leaders was most able to gain a parliamentary majority in support of their policies. Sahlin scored 45 percent on this measure, against 38 percent for Reinfeldt.
The Social Democrat leader was also rated most able to instill hope for a better future in people living in Sweden. 51 percent rated Sahlin higher on this measure, compared to 34 percent for Reinfeldt.
Support for Sahlin has strengthened in three of the four areas since Synovate last posed the questions. Only in the question of who was best at representing Sweden abroad was support unchanged.
Synovate quizzed 1,065 people between 1st and 4th October.
The debate between Reinfeldt and Sahlin will be shown on ‘Agenda’, SVT1, on Sunday at 9.15pm