The Liberals' voter support is measured at 3.0 percent in Verian's survey, an increase of 1.1 percentage points and the only statistically significant change compared with the last survey.
The Social Democrats' voter support is at 29.2 percent, down 1.3 percentage points compared with last time.
The Verian poll follows another poll from Wednesday by polling company Novus, which showed voter support of 3.3 percent for the Liberals and 25.8 percent for the Social Democrats - both down compared with previous Novus polls.
That poll showed a lead for the opposition that had shrunk to 2.6 percentage points.
"This shows that the election is by no means decided. If you want me as prime minister, you need to vote for the Social Democrats and the alternative is a government where the Sweden Democrats take control of the government and the state apparatus," S leader Magdalena Andersson told TT earlier on Thursday.
Do you feel like you need to add an extra gear now?
We were probably prepared to add an extra gear this last week, because it's clear many people have already decided and have already voted, but many are deciding now at the last minute.
Are you starting to get worried about this trend?
That the bloc difference would decrease is no surprise. Swedish elections tend to be close.
