GOP presidential front-runner Donald TrumpDonald TrumpTrump wants B for 62 miles of border wall: report Trump can boost national security, own legacy with Russian arms deal Press: Did Trump learn? MORE now has the support of 40 percent of registered Republicans, gaining 4 points in an NBC News/Survey Monkey national weekly tracking poll to reach a new high just before voters go to the polls on Super Tuesday.
Ted CruzTed CruzConservatism's worst enemy? The Freedom Caucus. Republicans giving Univision the cold shoulder: report How 'Big Pharma' stifles pharmaceutical innovation MORE, who’s in third place, slipped 1 point, to 18 percent, his lowest level in the survey.
Ben Carson ranks fourth, with 8 percent, while John Kasich follows, with 7 percent.
Pollsters also found that the overwhelming majority of GOP voters believe Trump will win their party's nomination.
About 71 percent predict Trump will become the Republican standard-bearer, up 15 points from a similar survey last week.
Rubio ranks second on that question, at 12 percent, while Cruz takes 10 percent, Carson 2 percent and Kasich 1 percent.
NBC News/Survey Monkey polled 8,759 registered Republican voters between Feb. 22 and 28. Their survey has a 1.8 percentage point margin of error.
Updated at 7:14 a.m.