British and Australian soldiers flew to northern Namibia Monday and immediately deployed to monitor the withdrawal of black nationalist guerrillas after fighting jeopardized a U.N. independence plan.

The 23 British and 64 Australian soldiers, part of the U.N. monitoring force, flew from the capital of Windhoek to Grootfontein town, then drove northward to assembly points and border posts.Starting Tuesday, guerrillas of the South-West Africa People's Organization are to report to the posts and assembly points for the peacekeepers to escort them back to bases in Angola.

About 1,900 guerrillas nearly derailed a U.N.-sponsored plan to bring independence to this former German colony when they crossed the border from Angola and heavy fighting broke out with South African-led security forces April 1.

A partially deployed U.N. monitoring force was criticized for not being able to check the incursions.

On Sunday, after South Africa reported at least 263 of his guerrillas were killed, SWAPO President Sam Nujoma ordered the insurgents to leave Namibia. South African, Cuban and Angolan officials agreed at a weekend meeting to give the guerrillas until Saturday to leave with a guarantee of safe passage. U.S. and Soviet officials observed the meeting at a Namibian game lodge.

Police reported calm in the northern bush for the second day Monday and said they are waiting to see whether the guerrillas obey orders to leave. The lull follows the fiercest fighting in the 23-year war for this mineral-rich territory, which South Africa has ruled since World War I.

Martti Ahtisaari of Finland, the special U.N. envoy in Namibia, told a news conference no official cease-fire is in effect, "but the South Africans have undertaken to restrain their forces."

South African Foreign Minister Pik Botha said of the guerrillas Sunday night: "If they do not attack, they will not be attacked."

At least 263 guerrillas and 28 security force members have been killed in the fighting, South African officials said. SWAPO says its losses were much lower and charges nearly one-fifth of those killed were civilians.

Ahtisaari said the United Nations will begin flying its flag at noon Tuesday at two churches south of the Angolan border and at seven along the border. The assembly points will be expanded to 18. The information also will be broadcast on the radio, he said through an aide.

The agreement was a major concession by South Africa, Ahtisaari said.

Botha said the guerrillas who assemble at churches inside Namibia will have to give their weapons to U.N. forces, who will then fly them to bases in Angola.

Guerrillas who travel to churches along the Namibian-Angolan border will be allowed to keep their arms and the Angolan government will take responsibility for returning them to their bases, Botha said.