Obasanjo noted that he hopes Nigeria signs “before it is too late”.
Forty-four African countries had last week signed the historic free-trade zone agreement.
It is the largest in the world since the creation of the World Trade Organisation in 1995. The African countries seek to form a $2.5 trillion continental free-trade zone.
The refusal to siggn according to the federal government was that a committee was reviewing the treaty and that it needs more input from stakeholders.
Reacting on Tuesday during a presidential panel at the Africa CEO Forum in Cote d’Ivoire, Obasanjo said: “That President Buhari didn’t sign the free trade agreement in Kigali is disappointing; I hope he signs it before it is too late.
“Egypt started the discussion on the formation of the Organisation of African Unity but didn’t conclude it and Nigeria took over.
“Nigeria was also central to the discussion of the free trade agreement, but I am surprised that the country withdrew from signing.”
Manufacturers Association of Nigeria (MAN) urged the government to renegotiate trade conditions that will impede economic growth in its review of the AfCFTA agreement.
“We are afraid that the rules of origin cannot be adequately enforced because goods from the EU can find their way into one of the African countries that have bilateral agreement with the EU,” Frank Jacob, president of MAN, had said.
“When the goods get into the African country, they can repackage them, change the label from made in Europe to that of the African country.
“That same goods will surely find its way to Nigeria which is the main target market for the EU.”