WASHINGTON (CNN) -- New Orleans Mayor Ray Nagin is seriously considering a Louisiana gubernatorial bid, a political intimate of Nagin tells CNN.

According to public records and his campaign treasurer, the two-term Democrat has raised more than a half-million dollars in campaign contributions since he was re-elected in 2006, even though Nagin can't run for mayor again. (New Orleans limits mayors to two terms.)

The mayor's senior staff members say Nagin is often approached on the street and asked if he'll run for governor, but they say he just laughs off the suggestion. At the mayor's State of the City speech Wednesday, many local politicians told CNN they'd heard the rumors.

If Nagin does decide to run for the state's highest office, it could be an uphill battle. A recent Loyola University poll showed Nagin had an approval rating of just 19% in New Orleans.

In March, current Democratic Louisiana Gov. Kathleen Blanco announced she would not seek a second term. Former Louisiana Sen. John Breaux, also a Democrat, entertained the notion of running for the post earlier in the year, but ultimately ruled against it.

On the GOP side, Rep. Bobby Jindal has announced he is running for the post.