In the poll released Thursday, 40 percent of Democrats backed Booker, while 25 percent said they would support Lautenberg. Notably, only 15 percent of surveyed Democrats said they wanted Lautenberg to return to the Senate.
Lautenberg has not yet said definitively whether he will seek re-election in 2014. Regardless of his plans, CQ Roll Call rates this race as Safe Democratic.
Only 26 percent of respondents said they were likely to vote for Rivera. The television personality indicated his interest in the Garden State Senate race last month.
The poll marks one the first reputable surveys to include additional candidates for the seat, including Rep. Frank Pallone Jr. and state Senate President Steve Sweeney. Pallone had the support of 4 percent of Democrats, while Sweeney had the backing of 2 percent.
Thirty-four percent of respondents said Lautenberg, 89, was too old to continue serving, while 48 percent said he was not. These views were similar to Monmouth's polling on the issue in 2008.
"The lack of concern over Sen. Lautenberg’s age is probably related to the fact that most voters have no idea how old he is," Monmouth pollster Patrick Murray wrote in a memo.
The poll also explored Sen. Robert Menendez's standing following reports questioning the Democrat's involvement with a political donor whose offices were recently raided by federal investigators.
Twenty-four percent of respondents "believed he was involved in wrong-doing," while 11 percent said Menendez is innocent. A vast majority of those polled, 65 percent, had no opinion or were not familiar with Menendez's troubles.
The poll was a telephone survey conducted among 697 registered voters with a margin of error of 3.7 percent. The poll was conducted Feb. 6 -10.