"It's been lodged and that's the only thing I can say to you," Hewitt's manager Rob Aivatoglou told Reuters.
Lawyers for the 22-year-old Adelaide resident lodged papers in the South Australian Supreme Court, a report on the Australian Broadcasting Corp. Radio website said.
The governing body for men's tennis said in April they were not intimidated by Hewitt's threat of legal action if the $20,000 fine imposed on the Australian for failing to show for an interview with host broadcaster ESPN at last year's Tennis Masters Series in Cincinnati was not waived.
The ATP originally fined Hewitt half of the prize-money he earned at the Cincinnati event -- some $105,650.
The world number two appealed and, after a two-day hearing in February, a three-member appeals committee confirmed the violation but reduced the amount to $20,000.
