The survey, from Kean University, gives Booker 49 percent support to 9 percent for both Rep. Rush Holt (D) and state Assembly Speaker Sheila Oliver, and 6 percent for Rep. Frank Pallone (D).

Nearly a fourth, or 22 percent, of respondents are still unsure of who they're supporting, an indication that the field is still fluid this early in the race.

Republicans chose former Bogota Mayor Steve Lonegan with 45 percent support, to 15 percent for physician Alieta Eck.

The poll was conducted among 1,000 likely voters on June 18, which makes it less reliable than multiple-day polls. But the results reflect every survey of the field so far, all of which have given Booker double-digit leads.

Following Sen. Frank Lautenberg's (D-N.J.) death last month, New Jersey Gov. Chris Christie (R) set a special election to fill the seat for Oct. 16, with the primary to be held on Aug. 13.

That choice rankled both Democrats, who said Christie was wasting state funds to help his own political goals by scheduling it on a different day from the upcoming gubernatorial race, and Republicans, who wanted Christie to hold the election in 2014 so the GOP could hold the seat for the rest of Lautenberg's term.

In the poll, a plurality agreed with Christie's decision to schedule the election prior to the gubernatorial election.

Christie himself posts a strong approval rating at 70 percent, and looks poised to easily win reelection, with 58 percent support to Democrat Barbara Buono's 28 percent support.

The survey has a margin of error of 3 percentage points.