Last week the Supreme Judicial Council increased the sentence to 200 lashes and six months in prison and ordered the rapists to serve between two and nine years in jail.
Ruling according to Saudi Arabia's strict reading of Islamic law, a court had originally sentenced the woman to 90 lashes for being alone with an unrelated man and the rapists to jail terms of up to five years.
It said she and her companion had been alone in a dark area outdoors, when they were noticed by the seven men who later raped them.
The court also took disciplinary action against the woman's lawyer, Abdul-Rahman al-Lahem, forcibly removing him from the case for having talked about it to the media.
"We reiterate that that judicial rulings in this virtuous country ... are based on God's book [the Quran] and the traditions of his Prophet [Muhammad] and that no ruling is issued without being based on evidence ...," the statement from the justice ministry, that was carried by the official news agency SPA on Saturday, said.
The ruling provoked rare criticism from the United States, which has invited Saudi Arabia to attend a Middle East peace conference in Annapolis next week.
A spokesman for the state department told reporters on Monday that "most [people] would find this relatively astonishing that something like this happens".
The US-based Human Rights Watch has called on King Abdullah, who last month announced plans to overhaul the legal system, to drop all charges against the woman.
The Saudi legal system is dominated by clerics who adhere to the kingdom's strict Sunni interpretation of Islamic law.