Mrs. Arroyo met survivors, rescue workers and the provincial governor Rosette Lerias for about one hour for an update on the massive international rescue operation.
But as her helicopter was about to take off, Imelda pushed her way past local officials and mud-splattered rescue workers to speak with the President.
The pilot had to reduce the rotor speed as Imelda briefly talked with the President before Mrs. Arroyo departed. Their comments could not be heard.
Imelda, widow of dictator Ferdinand Marcos who was toppled 20 years ago this week, strode back to hold an impromptu press conference.
Mrs. Marcos, wearing a formal black trouser suit, said she had traveled by road from Tacloban City where her family came from.
"As the first lady of this country and the mother of this country, this (tragedy) really overwhelms me," Imelda said, adding that she had canceled a trip to Hong Kong for medical treatment to see what she could do.
"The President, no less, is here to show her concern," she added, promising an unspecified donation.
Mrs. Arroyo, for her part, thanked the international community for its support, especially the United States, which has committed between 2,500 and 3,000 troops serving at the scene or on supply ships.
She also thanked Malaysia, Taiwan, Spain and Indonesia, which have sent doctors, nurses, troops or specialist teams to help in the rescue efforts.
The President, wearing a white shirt, black trousers and rubber boots, said Japan was sending geologists to survey earthquake-prone Leyte.
Up to 1,400 people are feared buried in Guinsaugon.