A new poll found DFL Gov. Mark Dayton has a 12 percentage point lead over Republican challenger Jeff Johnson, a slight expansion of the lead the pollster found last month.

According to the KSTP/SurveyUSA poll, Dayton would net 51 percentage points to Johnson's 39 percentage points with just one month before the election. In August, SurveyUSA had Dayton at 49 percentage points and Johnson at 40 percent.

The poll was conducted Sept. 30-Oct. 2 among

577 likely voters.

A Rasmussen survey of 750 likely voters conducted Sept. 29-30 found a similarly large lead for Dayton. That poll gave the DFLer a 10 percentage point advantage over Johnson.

Photos: Scenes from Gov. Mark Dayton and Jeff Johnson's debate last week. They will debate again on Wednesday. // Glen Stubbe, Star Tribune