A New York appeals court expressed skepticism on Thursday about a civil judgment of more than $450 million that a trial judge had ordered former President Donald J. Trump to pay after finding that he had fraudulently inflated his wealth.

At a hearing in Manhattan, members of a five-judge panel questioned both the size of the judgment and the validity of the case, which New York’s attorney general brought against the former president and his family business two years ago.

While some of the judges appeared supportive of the case, most expressed concern about whether the attorney general’s office had exceeded its jurisdiction. And the tenor of many of their questions suggested the possibility that the court could whittle down the huge judgment and potentially deal a blow to the attorney general, Letitia James.

Justice Peter H. Moulton, who seemed unswayed by many of the arguments by Mr. Trump’s lawyers, nonetheless said that “the immense penalty in this case is troubling.”

The trial judge in the case, Arthur F. Engoron, found Mr. Trump liable for civil fraud last year, concluding that he had lied about his wealth to secure favorable loan terms and other financial benefits. The judge imposed the judgment against the former president in February after a lengthy bench trial.

Judith N. Vale, New York’s deputy solicitor general, had barely begun addressing the court before one of the judges, David Friedman, interrupted her to cast doubt on the lawsuit. Other members of the panel inquired about possible “mission creep” by the attorney general’s office. They also questioned what “guardrails” might have ensured that Ms. James did not overstep her authority by second-guessing the net worth estimates that Mr. Trump had provided to lenders.