Wisconsin Republican Gov. Scott Walker has widened his lead over Milwaukee Democratic Mayor Tom Barrett heading into next Tuesday’s recall election, according to a new Marquette University poll.

Among likely voters, Walker leads 52 to 45 percent in the June 5 race sparked by his collective bargaining reforms. In Marquette’s last survey, taken in mid-May, Walker led by six points.

Overall, 51 percent of voters approve of the job Walker is doing while 45 percent disapprove. Barrett’s unfavorable rating (46 percent) is higher than his favorable rating (41 percent). Walker is viewed more favorably (51 percent) than unfavorably (46 percent).

Internal Democratic polling over the past few weeks has shown a very tight race. But public surveys give Walker an edge. In addition to the Marquette poll, a recent St. Norbert College-Wisconsin Public Radio poll found Walker leading by five.

The overall polling trend shows Walker with a narrow but steady lead over his Democratic rival, and Republicans are increasingly confident that the governor will hold his seat.

Among likely voters, Obama still leads former Massachusetts governor Mitt Romney, 51 to 43 percent in what is expected to be a swing state this fall. Republicans have argued that should Walker win the recall, it would aide their prospects pin the Badger State this fall.

The Marquette poll, conducted May 23 to 26, has a 4 percent margin of error.