The best-known leader of Manila's 1 million slum dwellers has been under military detention for the past two weeks and he lawyer claims that she "has been the victim of physical torture, specifically, electric shock.

"The woman, Mrs. Trinidad Herera, 35, is president of a slum community organization called "zotoz" which represents some 175,000 slum dwellers in the sprawling area known as Tondo in central Minila.She has also become the spokeswoman of Minila's slum dwellers generally.

In this informal capacity, she has conferred with World Bank missions working in Manila to help the government upgrade the slums and has frequently been invited to the presidential palace to talk with the President and the First Lady about slum problems.

Mrs. Herrera was quietly arrested on April 25. Neither the act of her arrest, nor the reason for it have been announced by the government.

Her lawyer, former Sen. Soc Rodrigo complained in a letter to top officials yesterday that he was not able to locate Mrs. Herrera until May 6th, when he found her in one of Manila's detention centers. He claimed that he was told by authorities at the center that his client was "sick" and could not be visited, but after much haggling he was finally allowed to see her.

In his letter, the lawyer said: "It took some time before she showed signs of recognizing me. I found it almost impossible to communicate with her. The few statements she made were evasive and incoherent."

Rodrigo said that he returned on May 8 with a doctor, but the doctor was refused permissions to enter the detention center and could only view Mrs. Herrera through a wire fence.

Inmates in the center have smuggled out unconfirmed reports that Mrs. Herrera was given electrical shocks on very sensitive areas of the body, and that she could not need or bathe herself for days after the torture. The reports said she would merely sit and stare blanky with tears rolling from her eyes.

Copies of Rodrigo's letter were made available to the press today. Officials spokesmen either disclaimed knowledge of the case or did not return reporter's calls.

In the past, President Marcos has said that "No one, but no one," is tortured under the martial law that he declared four-and-a-half years ago. Amnesty International sent an investigative mission to Manila in late 1975 and later claimed in a report that they considered torture to be "systematic."

Since Mrs. Herrera's arrest, three other Zoto leaders have been arrested quietly. Zoto is scheduled to have its annual meeting May 15th and the arrests are viewed as a way of disrupting the session. Zoto has normally opposed government plans for slum clearance whenever those plans have involved displacement of slum dwellers to the countryside.