United Nations (UN) Secretary-General Antonio Guterres said on Wednesday that travel restrictions imposed over Covid-19 that isolate any one country or region as "not only deeply unfair and punitive - they are ineffective."

Speaking to reporters in New York, Guterres said the only way to reduce the risk of transmission while allowing for travel and economic engagement was to repeatedly test travellers, "together with other appropriate and truly effective measures."

"We have the instruments to have safe travel. Let's use those instruments to avoid this kind, of allow me to say, travel apartheid, which I think is unacceptable," Guterres said.

Omicron was first identified in southern Africa and many countries, including the United States and Britain, have announced travel curbs and other restrictions on the region. Africa has some of the lowest Covid-19 vaccination rates worldwide due to a lack of access to doses.

Guterres has long warned about the dangers of vaccine inequality around the world and that low immunization rates are "a breeding ground for variants."

"These travel bans are not justified," said African Union Commission Chair Moussa Faki Mahamat at the joint news conference with Guterres after the annual meeting between the United Nations and the African Union.