"This amendment creates among others the positions of prime minister and vice-prime minister, the incumbent of which we expect to be sworn in with immediate effect," Motlanthe said in a statement.
Motlanthe welcomed the gazetting of the constitutional amendment, saying it was a "major step towards the formation of an inclusive government in Zimbabwe".
The amendment creates the position of prime minister, earmarked for opposition Movement for Democratic Change leader Morgan Tsvangirai, who signed a unity accord three months ago with President Robert Mugabe, though the two have so far failed to agree on how to form a cabinet.
Tsvangirai won a first round presidential vote in March, but pulled out of a run-off after a deadly campaign of violence, which he accused Mugabe’s party of orchestrating.
While lengthy negotiations have yielded the draft text on sharing out powers between president, prime minister and vice-prime minister, parties have warned there remain many issues around the formation of a unity government.
"These issues which are political in nature relate to issues of appointment of governors, ministers and others," MDC spokesperson Nelson Chamisa told AFP.
Zimbabwe, currently wracked by a cholera crisis, has spiralled into massive economic collapse during the political stalemate since first round elections in March.
"South Africa and SADC stand ready to assist the people of Zimbabwe as they embark on the difficult road towards the reconstruction and development of their country," Motlanthe said in his statement. – AFP