CNN

Corzine is behind in a new poll.

(CNN) - New Jersey governor Jon Corzine, burdened by a job approval rating of just over 40 percent, is losing ground in his 2009 re-election bid against the leading Republican challenger, a new poll suggests.

According to a Quinnipiac survey of New Jersey registered voters, Republican Chris Christie - a former U.S. attorney who made his name locking up corrupt public officials - now leads Corzine in a hypothetical match-up by a 44 to 38 margin.

That’s a 12-point turnaround from Quinnipiac’s last poll of the race in November, which showed a 42 to 36 lead for the incumbent.

The poll comes at a convenient time for the Christie campaign, which begins a two-day announcement tour Wednesday in Newark. Christie leads three other possible GOP candidates by a substantial margin.

A majority of voters say the governor does not deserve to be re-elected, and 45 percent say things have gotten worse in the state since Corzine became governor in January 2006.

But it’s not all bad news for Corzine: his Republican rival is still largely unknown. Sixty-one percent of voters say they don’t know enough about Christie to form an opinion of him.

National Republicans are eager for wins this November in New Jersey and Virginia, two states with off-year elections that are usually seen as a referendum on the party in power. In 2005, for instance, Democrats took both governorships, an early sign that George W. Bush’s political clout was waning heading into the next year’s mid-term elections.

The GOP has reason to be hopeful. Along with the prospect of a weakened Corzine in New Jersey, Virginia Republicans are fielding their strongest candidate in years with Attorney General Bob McDonnell, who can lay back until June while the three Democratic candidates in the commonwealth battle it out to win their party’s nomination.

The Quinnipiac poll of 1,173 registered New Jersey voters was conducted from January 29 to February 2, with a margin of error of 2.9 percentage points.