TRENTON, N.J.—A federal audit of New Jersey's "Stronger Than the Storm" marketing campaign, which featured Gov. Chris Christie and his family as he was running for re-election, found "nothing improper" in the use of the governor in the ads.

The audit, however, did fault the state for not complying fully with federal procurement rules.

The television commercials prominently featured Christie and his family, and they aired repeatedly last year, becoming a trademark of the state's recovery effort after Superstorm Sandy in 2012.

But they also raised controversy after Democrats and other critics questioned Christie, a Republican seeking a second term at the time, for his appearance in the ads, as well as the state's hiring of the East Rutherford-based MWW Group to conduct the marketing effort.

The U.S. Department of Housing and Urban Development's Office of the Inspector General began an audit of the contract last September in response to a letter from U.S. Rep. Frank Pallone, a New Jersey Democrat.

The 59-page audit, released on Wednesday, said that nothing in the content of the marketing campaign was "improper." The audit said Christie's appearance in the campaign violated no federal or state campaign laws and confirmed that MWW, which received the highest score from an evaluation committee, was also the lowest bidder.

The audit also determined that featuring Christie in the marketing effort played no role in the selection of MWW. Christie easily won re-election last year.

"The commercials did not identify the governor or his family by name or title, mentioned no state race or office, did not solicit funds for any purpose, and included no political message," the audit said.

But the audit also determined that New Jersey did not fully comply with federal procurement rules when it awarded the contract to MWW even though it certified that state rules were equivalent.

The audit faulted the Christie administration for not conducting a required independent cost estimate. The state used marketing efforts by Louisiana in the wake of Hurricane Katrina in 2005 to establish that it would spend no more than $25 million on marketing New Jersey after Sandy.

New Jersey has been providing more documentation requested by the federal agency to resolve other concerns raised in the audit, including questions about some labor and commercial airtime costs associated with the MWW contract, which included $19.5 million for marketing costs and $3.5 million for labor, the audit said.

"This is about differences between the state's procurement process and requirements and those of the feds," said Christie spokesman Kevin Roberts. "But the facts are the contract parameters were established, competitively bid, and we selected the best bid with the highest score."

Pallone issued a statement in response to the audit that stressed the procurement errors that were identified in the audit.

"Working with my New Jersey colleagues, I had to fight hard to get the Sandy aid package passed by assuring others in Congress that the funding was desperately needed and would be spent responsibly," Pallone said. "It is critical that we continue to ensure that all taxpayer funds from the Sandy aid package are being spent appropriately."

Josh Zeitz, MWW senior vice president, said the agency was "tremendously pleased" with the results of the audit.

"We said all along that our critics had no idea what they were talking about, and the Office of the Inspector General audit confirmed everything we said," Zeitz said.

Zeitz also pointed to data compiled by the state that showed marked job growth in the tourism industry last year, as well as increased hotel tax receipts and 1.25 billion total media impressions the number of times an ad is seen — for the marketing campaign.