"I hope political prisoners and journalists would be freed as soon as possible," Ebadi told her first news conference in Iran since she won the prize in a surprise decision on Friday.
Dozens of political activists, journalists and others have been jailed on vague charges of working against the Islamic establishment.
Ebadi, 56, a lawyer and rights activist, is hailed by reformers as a new beacon for their embattled effort to weaken the clerics' monopoly on power.
"The award put a heavy burden on my shoulders," she told the press conference. "I will not reduce my activities, I will increase them."
Her supporters hope Ebadi could use her international stature to force concessions from the regime. But Ebadi said she has no plans to stand in elections.
"I will never seek political power. A human rights activist should be among the people and speak for the silent population," Ebadi said.
Ebadi returned to Iran on Tuesday from Paris, where she was attending a conference when the Nobel announcement was made.
More than 5,000 people waited outside Tehran airport, staging the biggest pro-reform rally since violent street demonstrations in June. The airport terminal was crowded with supporters, including legislators, many of whom wore white to symbolize peaceful change.
Conservatives have denounced Ebadi as seeking to dismantle the Islamic system through Western-backed rights campaigns. State-run media, which are controlled by the hard-line wing of the establishment, did not immediately report her arrival.
Ebadi said Wednesday her priority is to push for change in the laws on the rights of women and children. She called on the hard-line clerics to stop blocking Iran's attempt to join the Convention on the Elimination of All Forms of Discrimination Against Women.
The reformist-dominated parliament passed a bill for Iran to join the convention in August, but the Guardian Council — a hard-line body that vets legislation — rejected the bill as contrary to Islam.
Ebadi also condemned violence in the name of Islam, but she made no mention of hard-line vigilantes who have often attacked pro-reform rallies.
"Whenever they kill people in the name of Islam, you should know they are misusing Islam because Islam is the religion of peace and justice," she said.
In a sign of Iran's division over Ebadi's winning the Nobel laurels, President Mohammad Khatami congratulated her Tuesday, but he also called the prize a "political" tool.
The double-edged comments by Khatami — who left for Malaysia before Ebadi's arrival — apparently sought to appease both hard-liners and reformists.
Ebadi was Iran's first female judge, but lost her post in the 1979 Islamic Revolution when the clerics barred women from the bench.
As a lawyer, she has represented the families of writers and intellectuals killed in 1999, and worked to expose conspirators behind an attack by pro-clergy assailants on students at Tehran University the same year.
The Nobel peace prize committee often awards prizes in the hopes of encouraging a laureate's work. In its announcement of the prize to Ebadi, the committee said, "We hope that the people of Iran will feel joyous that for the first time in history one of their citizens has been awarded the Nobel Peace Prize, and we hope the Prize will be an inspiration for all those who struggle for human rights and democracy in her country, in the Moslem world, and in all countries where the fight for human rights needs inspiration and support."