Federal investigators have ordered an audit to determine whether Gov. Chris Christie’s administration improperly spent millions of dollars of relief meant to encourage tourists to visit New Jersey after the devastation of Hurricane Sandy.

The audit comes as Mr. Christie is struggling with the most difficult crisis of his political career after it was revealed that people in his administration schemed to close local lanes onto the George Washington Bridge as political punishment for the Democratic mayor of Fort Lee. On Monday, New Jersey Democrats announced a new committee to investigate the closings.

This is not the first time Mr. Christie has come under criticism for the Hurricane Sandy funds: Many of the television advertisements used in the campaign, called “Stronger than the Storm,” prominently featured the governor and his family, which drew complaints from Democrats around the state who said it was more focused on promoting Mr. Christie than the Jersey Shore.