TRENTON -- Gov. Chris Christie is asking New Jersey's Republican and Democratic candidates for governor to help him in "pursuing a unified and continuous approach" to landing Amazon's second headquarters here.

The online giant announced earlier this month plans to build a second headquarters in North America, devoting $5 billion and hiring 50,000 workers. Municipalities and states across the U.S. are scrambling to meet the Oct. 19 application deadline.

In a letter sent last week, the governor, who leaves office in January, takes on an unusual role in appealing to both of his possible successors in an attempt to put New Jersey at the front of the pack.

"It will be important for Amazon to know that the next governor will be equally committed to bringing the HQ2 project to New Jersey," Christie wrote in the letter, obtained by NJ Advance Media.

Amazon wants to be in a metropolitan area within 30 miles of a population center, 45 minutes of an international airport and no more than one or two miles from major highways.

New Jersey's residents stand to gain some $9 billion in economic benefits if Amazon builds here, Christie stressed. The tax incentives would be worth about $5 billion, according to lawmakers.

In his letter to Republican Kim Guadagno and Democrat Phil Murphy, Christie outlines a list of goodies New Jersey could offer.

Among them, he asks the candidates to support his planned offer of tax incentives that last 50 years and at least $10,000 per job gained. Doing so will require the Legislature change rules for tax credits to remove existing caps and eliminate requirements for qualifying investments to be in economically distressed areas.

Christie has asked the candidates provide letters pledging their support by Friday.

A spokesman for Guadagno, Christie's lieutenant governor, said she hand delivered a written response Tuesday, said she "enthusiastically" supports New Jersey's efforts, including Christie's proposed legislation.

In an email to NJ Advance Media, a Murphy spokesman Derek Roseman said: "We will be submitting a letter."

Meanwhile, all four top Democratic and Republican leaders in the state Legislature issued a joint statement Wednesday pledging bipartisan support to bring Amazon's headquarters to New Jersey.

State Senate President Stephen Sweeney D-Gloucester said "we will work together and with Amazon on a plan that serves the best interests of the people of New Jersey."

State Assembly Speaker Vincent Prieto, D-Hudson, urged that "we need to do all we can to make this possibility a reality."

Senate Minority Leader Tom Kean Jr., R-Union, insisted "the bipartisan legislation that we've announced will improve New Jersey's competitiveness for Amazon's HQ2 and every other large-scale project that's looking for a home."

Assembly Minority Leader Jon Bramnick, R-Union, called it "a proposal lawmakers on both sides of the aisle can come together on, show unity and help provide the shot in the arm our economy needs."

NJ Advance Media staff writer Brent Johnson contributed to this report.

Samantha Marcus may be reached at smarcus@njadvancemedia.com. Follow her on Twitter @samanthamarcus. Find NJ.com Politics on Facebook.

Claude Brodesser-Akner may be reached at cbrodesser@njadvancemedia.com. Follow him on Twitter: @ClaudeBrodesser. Find NJ.com Politics on Facebook.