AP
The $25 million national ad campaign came at a time when Christie was running for re-election as governor.
U.S. Rep. Frank Pallone (D-N.J.) wrote a letter in August to the Department of Housing and Urban Development inspector general about his suspicions of the bidding process.
The winning firm charged about $2 million more to produce the ad campaign than the closest competitor. The firm that was awarded the bid planned to feature Christie in its ads. The losing bidder did not.
Pallone told CNN that a preliminary review by the inspector general determined that a full investigation was needed.
"This was money that could have directly been used for Sandy recovery. And, as you know, many of my constituents still haven't gotten the money that is owed them to rebuild their homes or raise their homes or to help," Pallone said.
Christie is already facing an investigation by state lawmakers into the closure of lanes onto the George Washington Bridge from Fort Lee, N.J., last September. New revelations stemming from that investigation - namely that some of his top aides and appointees were involved in the decisions to close the lanes - dominated national headlines last week.
Christie's office didn't immediately respond to a request for comment.