According to the BBC, AU head and South African President Cyril Ramaphosa has promised all of the doses will be used this year.
When pressed for details on the distributor and the cost for the vaccine, Ndembi said, "We have reached the final stage of our deals".
Africa has recorded more than three million infections, a fraction of the global figure of more than 91 million. The continent over the weekend surpassed 3 million confirmed cases since the start of the pandemic, with more than 1.2 million in South Africa.
The continent seeks to vaccinate about 780 million people, representing some 60% of its population of 1.3 billion.
The acquisition of 270 million doses will complement the 600 million doses expected to be made available to Africa by the COVAX initiative, a World Health Organization and Gavi Vaccine Alliance initiative to help low- and middle-income countries to secure access to vaccines.
Ndembi has said he's very optimistic that can be achieved within two years. The Africa CDC has warned that taking much longer than that risks having the virus become endemic in parts of the African continent. He gave no further details but said "we will make further announcements as we conclude our negotiations with vaccine manufacturers".
Arrangements have been made with Afreximbank to support member states who want to access these vaccines based on a whole-of-Africa approach.
The African Vaccine Acquisition Task Team (AVATT) which was established by African Union (AU) Chairperson President Cyril Ramaphosa on Wednesday reported to a special meeting of the AU Bureau of the Assembly that it has secured a provisional 270 million vaccine doses for African countries, with at least 50 million being available for the crucial period of April to June 2021.
"There is also close collaboration between the AU team and the World Bank to ensure that member states are able to access about US$5 billion, either to buy more vaccines or pay for delivery of vaccines committed on their behalf by Afreximbank", Ramaphosa said.
"Given the massive global demand for vaccines and the vastly greater purchasing power of wealthier countries, we are exploring all avenues to get as many vaccine doses as soon as possible", Ramaphosa said.