Union activist Neil Aggett complained in a sworn statement made shortly before his death in police detention that his interrogators had used physical violence against him and had kept him without sleep for two days and nights. The statement was made public here yesterday.

In the statement, made to a police sergeant 14 hours before Aggett's death Feb. 5, the activist said he was slapped in the face every time he disagreed with accusations made by his chief interrogator, whom he named as Lt. Stephan P. Whitehead, Washington Post special correspondent Allister Sparks reported. Aggett also said he was punched and kicked and had his testicles squeezed. His interrogators blindfolded him, handcuffed him with his hands behind his back and subjected him to electric shocks, according to his statement.

The statement was made public as a result of a police attempt to suppress it and overturn a decision to allow it to be submitted as evidence at the inquest into Aggett's death. But the police appeal to the Supreme Court of Transvaal Province, heard here yesterday, made the statement part of the Supreme Court record, so it became a public document.

The police deny mistreating Aggett, a white doctor who gave up medicine to work for a predominantly black trade union. They contend he hanged himself in his cell. He had been held by security police without charges since Nov. 27.

In his appeal, police lawyer Piet Schabort said the truth of Aggett's sworn statement could not be tested by cross-examination because Aggett was dead. The statement, therefore, was inadmissible, he contended.