WASHINGTON (AP) _ Two reporters will comply with a judge's order to reveal their sources in a civil lawsuit filed against 29 men, some of whom were involved in the Iran- Contra affair, a spokesman said Friday.

U.S. District Court Judge James Lawrence King in Miami said he was prepared to take action - even dismiss the lawsuit - if the reporters failed to divulge where they obtained the information that forms the basis for their allegations.

The Costa Rica-based freelance reporters, Martha Honey and Tony Avirgan, are represented by a legal team at The Christic Institute, a liberal public policy group.

''We have complied,'' said Peter Dykstra, a Christic spokesman. ''We've sent the information to him by express mail,'' he said.

King had set a Friday deadline to receive the information. The papers had not been filed in the Miami court by the close of business, but a night deposit box was open for mail. The judge was not in his chambers Friday afternoon.

The lawsuit claims the 29 defendants engaged in a wide-ranging conspiracy to help the Nicaraguan Contras and committed illegal acts, including an assassination plot to kill Eden Pastora, a former Contra leader.

The defendants, who have denied the allegations, include Contra leader Adolfo Calero; retired Gen. John Singlaub, and Richard V. Secord, who helped former National Security Council aide Oliver L. North run the Iran-Contra program.

Honey and Avirgan tried to keep their sources secret, claiming that their informants' lives could be endangered. But King and a U.S. Court of Appeals in Atlanta agreed with the defendants that the sources should be revealed.