Four Democrats and two Republicans will face off in their respective Aug. 13 primaries to try to replace Frank Lautenberg in the US Senate.

The seat was left open after Lautenberg’s death last week. A special election, to be held Oct. 16, was ordered by Gov. Chris Christie.

Among the Dems running are Newark Mayor Cory Booker, Assembly Speaker Sheila Oliver and Reps. Frank Pallone and Rush Holt.

Somerset physician Alieta Eck and former Bogota Mayor Steve Lonegan will vie for the GOP spot.

A Quinnipiac poll out yesterday suggests Booker is the Jersey guy to beat. The poll found that Booker nets 53 percent of the vote in a Democratic primary, followed by a lowly 10 percent for Holt and 9 percent for Pallone.