Seven African countries will start administering coronavirus antibody tests from next week, a regional body said on Thursday, as part of efforts to understand the extent of the outbreak on the continent.

"Liberia, Sierra Leone, Zambia, Zimbabwe, Cameroon, Nigeria, Morocco are the first set of countries that committed to it," said John Nkengasong, head of the Africa Centres for Disease Control and Prevention, based in Addis Ababa.

Western governments are using antibody tests to find out how many of their citizens have been infected, in the hope that will help them reopen their economies.

Africa has so far conducted 9.4-million coronavirus tests, a 10% increase over last week, Nkengasong said. These tests show whether people currently have Covid-19.

The continent's relative isolation has so far spared it the worst of the pandemic, but low levels of testing in many countries mean Africa's infection rates are likely to be higher than reported, experts say.

As of Thursday, Africa had recorded more than a 1-million cases of Covid-19 and 24 113 deaths, according to a Reuters tally.

Nkengasong said 25 African countries still have full border closures while 23 are imposing testing at entry points.

He stressed the need to harmonize border testing and recognition of certificates in order to facilitate travel.