CAPE TOWN, Monday

A REBEL South African police lieutenant who accused his colleagues of

brutality in suppressing unrest in coloured townships was arrested and

suspended today.

Gregory Rockman, classified as coloured (mixed-race) under apartheid

race laws, was charged with attending an illegal gathering after trying

to lead a small rally against his transfer from Mitchell's Plain near

Cape Town.

The country's police chief Hennie de Witt said Rockman and another

officer arrested in the protest had been suspended.

''The South African Police is a disciplined force and every member is

obliged to give effect to lawful instructions,'' Mr de Witt said in a

statement in Pretoria.

Rockman has risked action against him since he told reporters about

alleged police brutality in putting down unrest before segregated

parliamentary elections in September.

Two riot squad officers were charged on the basis of Rockman's

allegations, but were found not guilty of brutality and unnecessary use

of force.

Today's protest in Harmony Square was close to where Rockman alleged

white riot squads had acted like ''wild dogs'' when they broke up

anti-apartheid demonstrations.

Civil rights group say 20 people were killed in the election-eve

clashes with police but South African authorities say 19 died in mainly

tribal incidents.

In further defiance of police rules, Rockman formed a trade union for

policemen and prison warders last week.

Sixteen people, most of them prison wardens, were arrested with

Rockman at today's protest, at which demonstrators chanted slogans in

support of the trade union.

Rockman's commmanding officer, Colonel Johan Manuel, who is South

Africa's most senior coloured policeman and supports Rockman, has been

transferred to the same white police station at Pinelands, 10 miles from

Mitchell's Plain.

Meanwhile, two black South African political groups took opposing

positions today to President F.W. de Klerk's offer to discuss giving

blacks a share of power.

''The time to negotiate a new constitution has arrived,'' the central

committee of Zulu Chief Mangosuthu Buthelezi's moderate Inkatha movement

said in a newly-published document.

''We are determined to keep Inkatha ever ready to respond to any and

all opportunities to negotiate,'' said the group which claims to speak

for one million black South Africans.

The rival Pan Africanist Movement told a news conference in

Johannesburg its only ground for negotiations with Mr de Klerk would be

about the mechanics of a white handover to a socialist African

government elected by universal

franchiser.

Dismissing Mr de Klerk's offer of talks about a black role in the

central government, spokesman Benny Alexander said: ''The ideas of the

government must be ignored . . . rejected in their totality.''--Reuter.