Philippine President Ferdinand Marcos sharply denied tonight that his family was involved in the disappearance of a leading sports figure who reportedly married Marcos' daughter secretly in the United States last month. Marcos accused the missing man's family of "contemptible and cheap" efforts to defame him.

At the same time, the president ordered the military and police to use all efforts to find Tomas Manotoc, who officials say presumably has been kidnaped, and he called on the press and the Manotoc family to cooperate in the efforts to solve the case.

Marcos' angry reaction came five days after Manotoc, 33, a basketball coach and top amateur golfer, was reported missing after dining with Maria Imelda (Imee) Marcos in a Manila restaurant.

The Manotoc family has alleged official involvement in the disappearance.

Manotoc's family has reported that he was married secretly to Imee Marcos in an Arlington, Va., ceremony last month. The marriage was opposed by Imee Marcos' parents, largely because Manotoc already had been married, according to the Manotoc family.

Marcos' statement, issued by Malacanang Palace, criticized the Manotoc family for the allegations. He also assailed the foreign press for "using the same allegations without the slightest effort at verification."

"While we can understand and sympathize with the Manotoc family in their present travail, it is contemptible and cheap to make of this case an occasion to injure the good name of others," Marcos said in the statement.

The statement did not say directly whether Imee Marcos had been married to Manotoc, who was estranged from his first wife, Aurora Pijuan. According to Manotoc family sources, he divorced his wife in the Dominican Republic last month, since divorce is illegal in the predominantly Roman Catholic Philippines.

Without mentioning Imee Marcos' name, the statement said the president and his family cannot have any interest in the disappearance of Manotoc because a divorce obtained overseas is not recognized in the Philippines.

The statement said Manotoc remains married to Pijuan, with whom he has two children. "He therefore poses no problem to any member of the president's family," according to the statement.

The Manotoc family received a ransom note yesterday but has called it a fake.

Marcos' statement said that instead of cooperating with the authorities investigating the case, the family was more concerned about making propaganda against the president and his family.

"In the effort to establish the real identity of the kidnapers and the authenticity of the ransom note that Mr. Manotoc allegedly has written, obstacles have been posed and all kinds of absurd statements have been issued," it said. "These in turn have raised speculations about a possible plot to embarrass the president and his family."

The statement said Marcos was going to make every effort to recover Manotoc alive "so he can tell his own story."