Hu Na, considered to be the top woman tennis player in China, yesterday asked for political asylum at the Immigration and Naturalization Service in San Francisco.

Hu, 19, had been competing for China in the 20th annual International Tennis Federation Cup in Santa Clara, Calif.

She disappeared from her hotel last Wednesday, and Chinese officials had been unable to locate her since.

Yesterday, according to INS District Director David Ilchert, Hu and her lawyer came to his office and filed the papers necessary for seeking asylum.

Her lawyer, Edward C.Y. Lau of San Francisco, issued the following statement:

"She had informed the Chinese officials last week after she left the hotel of her intentions to defect. Why they chose not to go public with the information she did not know. She has been safe and comfortable in seclusion where she will remain until the State Department decides on her petition."

Lau's office would not elaborate on the statement, and he was unavailable for further comment.

A State Department spokesman said the department routinely provides an advisory opinion on asylum cases but that the final determination is made by INS.

Ilchert said that granting Hu asylum was not automatic.

"She has to prove that she'll be threatened or she'll undergo some kind of hardship if she goes back," he said. "We have denied applications before from people from the People's Republic of China."

Before her defection yesterday, Hu, a 5-foot-8 native of Szechuan who speaks no English, was last seen at her hotel Tuesday night. At that time, she told a friend she was going to read in bed before going to sleep. The next morning she was gone, but all her bags had been left behind.

Later the hotel received an anonymous telephone call saying that Hu was in a safe house and would seek political asylum.

But the Chinese women's tennis team issued a statement saying it was shocked over Hu's disappearance.

"Naturally we expect protection of our personal safety from the U.S. side," the statement said. The team returned to China on Saturday.

Jim Shen, a spokesman who traveled with the team to the United States, said everyone associated with the team was distressed over Hu's disappearance.

Hu is considered to have to potential to be a world class player. She won a tournament in Mexico last year and was the only woman selected to accompany a men's team to the United States two years ago.