A conservative backlash is emerging among hardliner conservatives of South Africa's ruling National Party, resulting in an effort to rein in party moderates who would prefer a faster pace of integration here.

Moderates have chosen to assuage the hardliners rather than confront them with a message that new attitudes in race relations ought to be adopted.

Last month, for instance, one delegate to a party conference publicly used the Afrikaans term that means "nigger lovers" and another complained about having to stand in line at the post office behind black "nannies and old manservants."

When they were criticized, a prominent Cabinet minister came to their defense, saying they were merely using "their own good right to express opinion."

Another Cabinet minister, meanwhile, was defending a City Council decision to keep nonwhites out of a new theater.

The ministerial comments appear to be part of a public attempt to curb party moderates who would like to see more opening up of such places as restaurants, theaters, beaches and hotels that now cater to the 4.5 million white minority and generally exclude the black majority that outnumbers whites almost five to one.

The first obvious salvo in that campaign came last month when Deputy Interior Minister Louis Le Grange told those he said were trying to "undermine" the party from the left to "get out of the party," which is dominated by the conservative Afrikaners.

A few days later, Connie Mulder, minister of plural affairs, the cabinet post dealing with nonwhites, stressed that public facilities would be shared by the different races only in limited cases.

"Certain people want to throw open everything in South Africa for everybody," he said. "This is neither policy now nor will it be in the future."

He was defending the Pretoria City Council's recent decision to prohibit nonwhites from attending performances at its Breytenbach Theater.

The council refused to alter its decision despite a campaign by arts patron P. Breytenbach, after whom the theater is named, to have it opened to all races. Ironically the theater bears the same name as the well-known Afrikaner poet, Breyton Breytenbach, who is serving a nine-year jail term on terrorism charges.

The action by the City Council attracted wide attention since it followed a refusal by Israeli Ambassador Yitzak Unna to attend a premier showing of the new play "Golda" at the Breytenbach because the theater was not open to all races.

Moderates in matters of racial discrimination - most notably Foreign Minister Pik Botha - openly criticized the council decision. Mulder's remarks this week were, as one Afrikaner put it, "a slap in the face to Pik."

Last month, right wing delegates to a provincial National Party congress in the coastal town of Durban complained that apartheid, the government's policy of separation of the races, was being "watered down" and the party was becoming filled with "nigger lovers" because of recent moves to open more public facilities to all races. One man said he would never again attend a local trade fair because he had been swamped by blacks and another said he could no longer send his daughter alone to the beach out of fear blacks would molest her.