JOHANNESBURG, SEPT. 9 -- The black-consciousness Azanian People's Organization charged today that its members are being harassed by security police in an effort to stop memorial services planned for the 10th anniversary of the death of leader Steven Biko.

The group said it would seek a court order restraining authorities from interfering with the commemoration of Biko's death or the planned unveiling of a monument Saturday in Biko's home of Ginsberg, near East London.

The organization's publicity secretary, Muntu Myeza, said at a press conference here that about 20 of the group's members in the black township of Soweto were detained by police yesterday and that pamphlets, stickers and placards had been seized.

He said that the group's chief administrator, George Wauchope, was arrested Friday, and that three officials of the group who were sent to Ginsberg to make arrangements for a memorial service were detained by police, interrogated and ordered to leave the area. Biko died at the age of 30 of brain injuries following five days of interrogation by security police.

A police spokesman in Pretoria confirmed that three people had been questioned in King William's Town, near Ginsberg. But the police denied that members of the Azanian People's Organization were being harassed and said no restrictions had been placed on the Ginsberg memorial.

Myeza said that at least nine services will be held to mark the anniversary of Biko's death.

The black-consciousness movement led by Biko dominated black politics a decade ago but lost much of its influence following a police crackdown and the emergence of the United Democratic Front, a coalition of 700 groups opposing the system of strict racial segregation known as apartheid.