How much illegal music downloads would cost? For a U.S. woman it's $US222,000 as determined on Tuesday by a federal appeals court, which declared that the hefty fine was just and reasonable.

The woman's misdeed, according to The Associated Press (AP), was opening up her digital library of about 1700 songs through file-sharing site Kazaa and in the process earning the ire of the Recording Industry Association of America (RIAA).

The generosity displayed by the defendant, identified by AP as Jammie Thomas-Rasset of Minnesota, did not sit well with the RIAA, which in 2006 found a way to trace the illegal activities and haled her to court.

Three trials ensued in the suit and Ms Thomas-Rasset was found guilty and made to pay an original amount of $US1.5 million to cover for the losses that RIAA said have been taking their toll on the U.S. music industry.

However, lower court Judge Michael Davis thought that the whopping fine was both "severe and oppressive," and cut down Ms Thomas-Rasset's liability to mere $US54,000, setting off another trial that led to the current fine level.

On Tuesday, the appeals court ruled that the defendant deserves the steep penalty and ordered Mr Davis to revise his earlier ruling, insisting too that Ms Thomas-Rasset must pay the full amount awarded to RIAA by the last jury.

That means she would have to pay roughly $US2,250 for less than a hundred songs.

In a statement, Ms Thomas-Rasset's defence counsel, Kiwi Camara, said that they will elevate the case to the U.S. Supreme Court, arguing that the award was "punitive."

The defendant confirmed that the latest ruling would be difficult for her since her resources would be no match to the amount that the RIAA would be getting from her. She has no recourse but to go along with another round of appeal, AP said.

But analysts were in doubt if the American High Court will even consider hearing Ms Thomas-Rasset's case, citing the similar legal being faced by a former Boston University student Joel Tenenbaum.

Mr Tenenbaum, according to AP, was successfully prosecuted by the RIAA, leading to a jury awarding $US675,000 to the music industry group.

His attempt for the Supreme Court to review the case was turned down on May 2012.

In a statement, the RIAA said "we are pleased with the appellate court's decision and look forward to putting this case behind us."

It is understood that the parts of the payment ordered by the court will be donated to charity as earlier indicated by RIAA officials.

The ruling was handed down following reports this week that Internet users who are frequenting BitTorrent sites, which offer file-sharing services, could be under the close watch of monitoring groups tasked to log the IP addresses of free download fans.

However, the same report maintained too that these groups would not able to build a strong case against persons they suspect were obtaining illegal copies of copyrighted materials. For one, the tools they currently employ would fall short of proving that BitTorrent visitors were actually downloading files while logged on, the report added.