MANILA, Philippines (AP) _ President Corazon Aquino said in an interview broadcast Wednesday that she may give amnesty to former President Ferdinand E. Marcos if he returns some of the money he allegedly stole from the nation.

She also defended herself against criticism that she lacks firmness as a leader and appealed for time to ''get everything together, time to get everything organized.''

The president said a convention would open June 2 to start drafting a constitution to replace the one her government scrapped.

The interview, which was taped Monday, was conducted by Luis Beltran, editor in chief of the Philippines Daily Inquirer, which initially supported Mrs. Aquino but has become increasingly critical of her government.

Mrs. Aquino, 53, did not say what kind of amnesty she would offer Marcos, who fled the country for Hawaii Feb. 26 in the face of a military-civili an revolt that installed her as president after Marcos was declared the winner of a fraud-tinged election.

Marcos, family members and other associates have been accused of stealing at least $5 billion during his 20-year rule. Mrs. Aquino said previously that she would forgive Marcos if he returned the money, but this was her first mention of amnesty.

''At least part or a greater part of the whole is better than nothing at all, and we feel that maybe we can get this (money) coming back faster if we will be able to offer them amnesty,'' Mrs. Aquino said.

The president also said she would continue to show tolerance for supporters of Marcos, including demonstrators who have camped for days in front of the U.S. Embassy in Manila and demanded the United States allow Marcos to return. Pro-Marcos forces have accused the United States of ''kidnapping'' their leader so Mrs. Aquino could take office.

Mrs. Aquino has barred Marcos from the Philippines until political stability is restored.

During the interview, Mrs. Aquino also:

-said a convention would open June 2 to begin drafting a constitution to replace the interim document she promulgated last month after scrapping the old constitution. Mrs. Aquino said she would name the convention delegates. She said a draft constitution should be completed by Sept. 2 and submitted to voters within two months.

-said she would appoint an ambassador to Moscow soon, filling a post that has been vacant since 1982. Mrs. Aquino said she did not know why the post was vacant so long.

-accused Manila newspapers of distorting news about her government and said there has been too much criticism.

-said generals over retirement age will step down in six months, with the exception of armed forces chief Gen. Fidel V. Ramos, who helped lead the rebellion that put her in office.

In another development Wednesday, Ramos authorized military commanders on Mindanao island to arrest anyone who shows up Friday for a planned meeting to declare the island an independent nation.

The convention was called by Reuben Canoy, leader of the Mindanao People's Democratic Movement, in Cagayan de Oro, 500 miles south of Manila. Canoy said the convention will approve a constitution proclaiming the Federal Republic of Mindanao.

The military issued a statement saying, ''The move to form a Mindanao Federal Republic ... is illegal, seditious and constitutes rebellion.''

The fertile, mineral-rich island of 37,000 square miles is largely undeveloped and poorer than most other Philippine areas. A Moslem group, the Moro National Liberation Front, waged a violent struggle for independence in the 1970s, but fighting there has abated.

Mrs. Aquino said in the interview that she has ordered Cabinet members not to fire low-level government employees just because they supported Marcos.

''If we will do that, no one will be left in the government, because after 20 years almost everyone has links to Marcos,'' she said. ''I'd much rather let one guilty person go rather than crucify one innocent person.''

Although Mrs. Aquino's supporters have claimed that a wide variety of crimes were committed by Marcos officials, only one has been arrested - former Assemblyman Orlando Dulay, who escaped earlier this month after being charged with political murders.

Mrs. Aquino said anti-government demonstrations will be allowed as long as they are non-violent.