In the survey of 1000 Swedes carried out by pollsters Sifo for newspaper Svenska Dagbladet in June, 49 percent said they did not want Sweden to join Nato, 33 percent said yes, and 18 said they were undecided.
The results suggest public opinion has changed since the last Sifo survey on the topic in September of 2015. In that poll, 41 percent said they were in favour of Sweden seeking Nato membership, 39 percent said they were against, and 20 percent were undecided.
At the time, the 2015 figures appeared to demonstrate a significant shift in public opinion in the traditionally non-aligned Nordic country, but Sifo's most-recent round of results indicate that shift was short-lived.
Sifo survey manager Toivo Sjörén told SvD that one reason for the latest change in opinion could be resistance to Nato membership from leading Social Democrat politicians.
According to Sifo's poll, opposition to Nato membership in Sweden is at its strongest among voters for the Social Democrats and the Greens, and in particular, Left Party voters.
Middle class voters meanwhile are more likely to say yes than no to membership, regardless of which party they support, with the exception of the Centre Party.
The strongest support can be found among Christian Democrat voters, while Sweden Democrat voters are more likely to be pro-Nato than against, despite the party's negative stance towards membership.
Earlier this week Sweden's former foreign and prime minister Carl Bildt predicted that the country will join Nato in less than ten years, citing fears over Russia's “increasingly authoritarian tendencies” as a driving factor.
In May, the Riksdag voted through a so-called Host Nation Support Agreement (HSNA) with Nato which allows the alliance to transport helicopters, aircraft and ships across Swedish territory upon Sweden's invitation.
The 2016 Nato summit begins in Warsaw, Poland this Friday.