South Africans expect the country's last racial segregation laws to begin crumbling Friday when President F.W. de Klerk makes his opening of Parliament speech and fulfills a promise to press on with reforms he launched a year ago.

But in action to coincide with the Cape Town speech, almost every black anti-apartheid group will stage mass protests across the nation to press their demand for full power-sharing for the black majority..Scorning anything less than an end to white minority rule and the immediate introduction of a temporary legislature of all races to precede a non-racial parliament, black leaders have promised their mass marches, protests and strikes will go ahead.

"We demand an assembly of all races, not half measures. Our action will show we are serious," African National Congress leader Nelson Mandela said earlier this month.

Leaks to the press and hints from Pretoria in recent weeks point to an announcement by de Klerk of the abolition or radical amendment this year of the Group Areas Act, which determines where races may live, and the Land Acts that reserve more than 87 percent of land for whites.

De Klerk may announce his intention to scrap the last of the pillars of apartheid, the Population Registration Act, which registers people by race at birth. He is believed ready to commit the government to a single education system, ending white privilege in schooling, and to do away with black municipalities.