Mrs. Arroyo's announcement came in response to a call by the country's influential Catholic bishops, who said she must address charges that she rigged last year's election.
In a statement to the Philippine Catholic Bishops Conference, Mrs. Arroyo said she was forming a truth commission to investigate the charges.
She also reiterated her determination to stay on the job, saying the issue has been "manipulated" by groups out to "grab power." In a speech before Filipino diplomats, she said it was more important to focus on improving the economy.
"The task at hand is to unite and speed up economic growth and to keep the confidence of the markets and our trading partners," she said.
The political crisis was sparked by a secret recording of conversations between Mrs. Arroyo and a senior election official, which was made as the votes were being counted last year. Mrs. Arroyo has admitted the voice was hers and apologized for making the call, but denied she had influenced the results and refused calls for her to resign.
Instead of defusing the issue, Mrs. Arroyo's admission increased the pressure against her. Key allies began joining the calls for her resignation, and 10 of her ministers resigned.
The crisis led international ratings agencies to downgrade the Philippines' credit rating from stable to negative last week, making it more expensive for the impoverished country to borrow money overseas.
Last week, the Bishops' Conference stopped short of asking Mrs. Arroyo to resign, a decision some analysts say may have saved her political career. Instead, the group urged her to address the issue directly in order to restore public trust in government.
Mrs. Arroyo has managed to rebuild her government during the past week. But the opposition continues to pursue efforts to oust her. A number of lawmakers said they were planning to file impeachment charges against her in Congress as early as next week.
Political analysts say an impeachment is unlikely to succeed, because her party holds a majority of seats in Congress.
Mrs. Arroyo's predecessor, Joseph Estrada, faced an impeachment trial in 2001 for corruption, but the trial was cut short when mass public protests forced him from office.