At least 14 people were killed and more than 30 wounded today when a bomb exploded in a bank branch office near a military base in South-West Africa, the territory also known as Namibia.
The attack at Oshakati, a civilian-military complex about 25 miles from the northern border with Angola, was believed to be the deadliest to have occurred in the territory during the 22-year-old war between South African-led security forces and guerrillas fighting from bases in Angola.
There was no claim of responsibility for the blast. The South African authorities told The Namibian, a newspaper in Windhoek, that the attack had been carried out by the South-West African People's Organization, the main guerrilla group opposing South Africa's occupation of the territory. But the rebel group, in a statement issued tonight in Luanda, Angola, denied this. 'Dirty Propaganda Campaign'
Hidipo Humutenya, the rebels' information secretary, said the attack was part of a ''dirty propaganda campaign to smear the name of Swapo.''
The explosion occurred about 1 P.M. and destroyed the branch of the First National Bank in Oshakati, home of a major base for the territorial security force. The base is also a staging area for South Africa's recent intervention in Angola's civil war.
South African military spokesmen said 13 of those killed were black and one was white. Of the 31 wounded, 28 were in serious condition. Many of the victims were believed to be government workers who had gone to the bank to collect their weekly wages. [ Reuters quoted witnesses at Oshakati as saying that the bomb blast, the second at the bank in about a year, threw limbs and wreckage into the street and that police fired tear gas to disperse panicked crowds after the explosion. The earlier bomb blast killed one person and injured four. ] The South-West African rebel group's membership is largely drawn from the majority Ovambo ethnic group, which occupies a 70-mile-wide strip of land along the Angolan border.
Western diplomats said tonight that the attack seemed a highly counterproductive act for the rebels to have committed, since all the blacks killed were members of the Ovambo group.
Recent bomb attacks for which the South-West African guerrilla group has claimed responsibility have been directed at targets in Windhoek, the seat of the Pretoria-installed ''interim government.'' No one was killed in those attacks. Cuban Role in Angola
South Africa rules the territory through semi-autonomous internal structures in defiance of several United Nations resolutions. South Africa and the United States contend that there can be no solution to the question of Namibian independence until some 40,000 Cuban troops leave neighboring Angola.
For the last five months, a South African invasion force estimated at 6,000 has been fighting several hundred miles inside Angola against Cuban-backed Angolan forces waging a 12-year-old war against anti-Government rebels led by Jonas M. Savimbi.
The bank building in Oshakati may have been particularly crowded today because Friday is the day black employees of the Ovambo administration, a regional tribal authority, are paid their weekly wages.