Lawyers for thousands of sickened Ground Zero workers must justify making their clients cover the cost of loans that helped finance their suits, a Manhattan federal judge ordered yesterday.

The ruling by Judge Alvin Hellerstein came after The Post revealed that the law partnership of Worby Groner Edelman & Napoli Bern is charging 9/11 responders interest rates that range from 6 to 18 percent.

Lawyer Paul Napoli has insisted that his firm isn’t making any money on the deal.