A new poll shows Newark Mayor Cory Booker’s commanding lead in the 2014 primary in New Jersey has increased since Sen. Frank R. Lautenberg’s retirement announcement.

Half of the respondents said they would back Booker in a new Fairleigh Dickinson PublicMind survey — a score that’s increased by 8 points since a similar January poll.

Rep. Frank Pallone Jr., another Democrat who has expressed interest in the Senate race, picked up 4 percent in the poll. Meanwhile, 7 percent supported Democratic Rep. Rush D. Holt, who has also floated his name as a contender. Thirty-two percent of respondents were undecided.

TV personality Geraldo Rivera, a Republican who has openly mulled a run for the seat, did not perform well in this poll. Booker had a 31-point lead over Rivera in the survey.

The survey questioned 702 registered voters via cellphone and land-line interviews from March 4 to 10. The poll had a margin of error of 3.7 points.

The Democratic subsample included 323 respondents with a margin of error of 5.5 points.