Ramtane said the sanctions would involve stringent measures such as the freezing of bank accounts and travel visas for on the leadership of the National Council for Democracy and Development (CNDD).
The AU had previously threatened sanctions if Camara, who promised to rein in the army and transfer power to civilian rule through elections, refused to opt out of a poll set for January.
A list of persons targeted by the sanctions is to be sent to the United Nations, the Arab League, the Organisation of Islamic Conference and a grouping of French-speaking countries in order to give the measures "a universal character", a statement said.
International pressure and internal dissent have grown in Guinea since live ammunition was used against the protesters as they gathered in a stadium in the capital, Conakry.
The United States, France and the European Union have all called on Captain Moussa Dadis Camara, who has served as president since the coup, to step down, while the International Criminal Court has said it is investigating the killings.
Human Rights Watch said in a report released on Tuesday that the killings were premeditated.
It also accused security forces of taking dozens of women from a stadium and driving them in military vehicles to villas where they were raped by uniformed men over several days.
The military government has admitted that 56 people died and 934 were wounded.
Inside Guinea, thousands of ordinary citizens showed their continuing anger at the deaths by staying at home for a second consecutive day.
Dozens of people began a five-day hunger strike, organisers said.
The EU agreed on Tuesday to impose an arms embargo on the West African country, and restrict the travel and freeze assets of those involved in the killing of the protesters.
The US government has also restricted travel to the United States by some of the ruling members as well as others who support actions that "undermine the restoration of democracy and the rule of law".