Lubna Hussein was among 13 women arrested July 3 in a raid by the public order police in Khartoum. Ten of the women were fined and flogged two days later. But Hussein and two others decided to go to trial.
"I will not pay a penny," she told the Associated Press while still in court custody.
Hussein said Friday she would rather go to jail than pay any fine.
"I won't pay, as a matter of principle," she said. "I would spend a month in jail. It is a chance to explore the conditions of jail."
The case has made headlines in Sudan and around the world, and Hussein used it to rally world opinion against the country's strict morality laws based a conservative interpretations of Islam.
Before the trial, Sudanese police rounded up about 40 women protesters outside the courthouse where they were showing support for Hussein.
Some of the women protesters were wearing pants themselves.
The London-based Amnesty International called on the Sudanese government to withdraw the charges against Hussein and repeal the law which justifies "abhorrent" penalties.
Human rights and political groups in Sudan say the law is in violation of the 2005 constitution drafted after a peace deal ended two decades of war between the predominantly Muslim north and the Christian and animist south Sudan.
Hussein, who was released on bail during the hearings, has sought to draw international attention to her case and battle the law she has described as un-Islamic and oppressive to women.
The Amnesty statement issued Friday said Sudan had been urged to amend the law which permits flogging, on the grounds that it is state-sanctioned torture, after eight women were flogged in public in 2003 with plastic and metal whips leaving permanent scars on the women, Amnesty reported. The women had been picnicking with male friends.
As a U.N. staffer, Hussein should have immunity from prosecution but she has opted to resign to stand trial in any case.
In a column published in the British daily the Guardian Friday, Hussein said her case is not an isolated one, but is a showcase of repressive laws in a country with a long history of civil conflicts.
"When I think of my trial, I pray that my daughters will never live in fear of these police ... We will only be secure once the police protect us and these laws are repealed," she wrote.
Hussein said earlier she would take the issue all the way to Sudan's Constitutional Court if necessary, but that if the court rules against her and orders the flogging, she's ready "to receive (even) 40,000 lashes" if that what it takes to abolish the law.
By Associated Press Writers Mohamed Osman and Sarah El Deeb