Forty-nine of the 55 member states of the African Union have signed the continental free trade are agreement.
The AU chairman Rwandan President Paul Kagame made the announcement on Monday during the closing ceremony of the 31st African Union Summit in Mauritanian capital Nouakchott.
South Africa, Sierra Leone, Namibia, Lesotho and Burundi signed the African Continental Free Trade Area (AfCFTA) agreement in Nouakchott, bring the number of countries that have inked the deal to 49.
Chad and the Kingdom of eSwatini joined four other countries that have ratified the agreement.
The AfCFTA will come into effect after 22 countries ratify it.
It will be the largest free trade area that creates an African market of over 1.2 billion people with a GDP of $2.5 trillion.
The deal has four legal instruments: The framework agreement establishing the AfCFTA; the protocols on trade in goods; protocol in trade in services; and the protocol in dispute settlement.
The agreement is expected to remove taxes from up to 90 per cent of the 200 items traded on the continent, making them cheaper for consumers.