South African President Cyril Ramaphosa has once again urged countries that have put travel bans on southern African due to the discovery of the Omicron variant of Covid-19 to reverse these decisions, describing them as discriminatory, unscientific and counterproductive.

He was speaking at a joint press conference with the Nigerian President Muhammadu Buhari in the presidential palace in Abuja.

A number of western, and African, countries have recently banned travellers from several southern African nations after the Omicron variant was detected in the region.

The region's leaders are united against such blanket bans because of their potentially considerable and long-lasting economic damage, Mr Ramaphosa said.

Mr Ramaphosa and Mr Buhari had a closed-door meeting and then announced that they had signed a memorandum of understanding in several areas including youth development and women and child advancement.

The agreement will enhance meaningful interaction between the youth of the two largest economies in Africa, Nigerian President Muhammadu Buhari said.

In recent years, xenophobic attacks in South Africa targeting other African nationals including Nigerians have caused tension.

The South African leader is on a four-nation tour of West Africa.