In the Monmouth University Poll, Booker takes 63 percent support to 10 percent for Rep. Rush Holt, 8 percent for Rep. Frank Pallone and 6 percent for state Assembly Speaker Sheila Oliver.

That's largely due to Booker's strong name recognition in the state, with three-fourths of likely special election voters having an opinion of the mayor, while only 40 percent have an opinion of the other three candidates.

Booker also leads the presumed GOP nominee, Steve Lonegan, by a wider margin than any other Democrat in the race, taking 53 percent to Lonegan's 37 percent support. The three other Democratic contenders still lead him, but all by single digits, ranging from 5 to 2 percentage points.

Though the Monmouth University Poll brings Booker good news, it may trouble Democratic gubernatorial candidate Barbara Buono, who will face New Jersey Gov. Chris Christie (R) on the ballot this November.

The poll was conducted among 636 likely New Jersey special election voters from June 10-11, and has a margin of error of plus or minus 3.9 percentage points.