South Africa's new administrator-general in Namibia, Willie van Niekerk, is sounding out local political parties on a plan to hold new elections in the territory, making it clear that his government no longer expects an early settlement on Namibian independence.

This contrasts with the optimistic forecasts made repeatedly by both the South African and U.S. governments since the Reagan administration began the search for a Namibian settlement in mid-1981.

"Because there is no sign of progress toward the removal of the Cubans in Angola, implementation of a settlement plan is a matter of uncertainty," van Niekerk's chief aide, Sean Cleary, said in a telephone interview from Windhoek, the Namibian capital.

Because of the expected delay, van Niekerk is talking to local party leaders about a proposal that South Africa unilaterally organize elections in the territory. These would be to elect members to what he is calling a "constitutional development committee" which would draft a new constitution for Namibia.

Sources close to van Niekerk say he wants to reactivate Namibia's internal parties, which went out of business last January when South Africa dissolved the National Assembly in Windhoek, because he is worried they may atrophy during a long wait for implementation of a negotiated settlement.

They would then be unable to form an effective opposition to the South-West African People's Organization, the radical black insurgent movement which is fighting to end South African administration of the territory, should independence elections eventually be held.

Although there is understanding in U.S. diplomatic circles here for van Niekerk's desire to keep the internal parties active and alive, there is also concern that the holding of another South African-organized election could jeopardize the negotiations.

The last such election, which established the National Assembly in 1978, proved a setback to settlement negotiations, then led by the Carter administration, which later broke down.

One diplomatic source here said there was concern that news of the van Niekerk plan might adversely affect neighboring Angola's response to continuing feelers for a cease-fire in the Namibian border war.

The source also expressed concern that it might cause tensions within the western five-nation contact group through which the United States has been working. Though the source did not name any country, France is thought here to be the contact group member most unhappy about the new developments. The French Embassy in Luanda has played a key role in the negotiations with Angola.

The political vacuum in Windhoek which van Niekerk is anxious to fill arose because of a row between the South African government and Dirk Mudge, leader of Namibia's main internal political movement, the Democratic Turnhalle Alliance.

Mudge had been complaining for months that Pretoria was undermining his attempts to build black support for his moderate alliance by insisting on the retention of segregationist laws and practices to satisfy members of its own all-white National Party in the territory.

He finally resigned as chief minister in January and withdrew his alliance from the National Assembly. Daniel Hough, van Niekerk's predecessor as administrator-general, then dissolved the Council of Ministers and the National Assembly and took over direct administration of the territory himself. Van Niekerk, a gynecologist and a member of a council that advises South African Prime Minister P.W. Botha, took over from Hough three weeks later.

Van Niekerk has now made the rounds of the territory's more than 40 parties, outlining three options: that he continues to rule directly; that the parties come forward with a proposal for their involvement; or that there should be an election for the "constitutional development committee."

Party members say he is pushing the third option and wants a 72-member committee: 50 elected on a basis of proportional representation after one-man-one-vote elections, and two nominated from each of Namibia's 11 ethnic groups.

Cleary, van Niekerk's aide, said the talks were finding a "remarkably large degree of agreement among the parties that there should be some kind of political development."

However, some party leaders interviewed sounded skeptical. Kosie Pretorius, leader of the National Party, said that although his party had not adopted a formal position, it was in principle against participating in one-man-one-vote elections except on separate ethnic rolls.

Johan de Waal, general secretary of the Democratic Turnhalle Alliance, said his party's executive would reach a decision Monday but was in principle against participating in any process "unless it is going to lead to something specific."

"We are not interested in something just devised to keep us busy and stop us shouting at South Africa," de Waal said.

Van Niekerk is due to wind up his talks with the internal parties Monday. Cleary said he thought there would have to be another round of talks after that, but he hoped the administrator-general would be in a position to announce his intentions before the end of next week.