The agreement followed the Iraqi National Assembly's approval for a partial cabinet lineup.
The government will be sworn in at 5pm (1300 GMT) at a ceremony in the Green Zone, a high-security area in Baghdad which is home to parliament and the US embassy, government protocol chief Jasim Msawil said.
It was not immediately clear if all ministry posts had been filled or if some interim appointments that were agreed to on Thursday would remain in effect.
Al-Jaafari and Sunni Arab legislators reportedly reached a deal on Monday to appoint Sunni Arab figures chosen by them as ministers in the interim government.
In an interview with Aljazeera on Monday, Iraqi MP Mishaan al-Jiburi said Sunni Arabs had been under-represented at the ministerial level.
"Several parties have attempted to appoint representatives for us in the government based on their own values and points of view, but in the end our viewpoint has prevailed," al-Jiburi said.
"However, we regret that others were able to veto our nominees, without us Sunni Arabs having the same power of vetoing their nominees."
The MP noted that while Shia politicians had vetoed Sunni nominees, Sunnis had not been empowered to use any veto themselves.
Al-Jiburi said that while nobody could claim to represent Sunni Iraqis - due to election boycotts and a fragile security situation - two issues were of particular concern to them.
"Freeing detainees and reconsidering the law for eliminating the Baath Party ... these are Sunni Arab demands which the Iraqi government has pledged to include in its official speech tomorrow," he said.
Al-Jaafari announced a partial lineup last Thursday after several weeks of political haggling, but several key posts were left vacant and Sunni leaders complained of under-representation.
Mishaan al-Jiburi: Others have
been able to veto our nominees
The rest of the lineup, presented below, is expected to be submitted for parliamentary approval on Tuesday.
Deputy Prime Minister: Mutliq al-Jiburi
Defence Minister: Major-General Ahmed al-Raikan
Industry and Minerals Minister: Mejbil al-Sheikh Issa
State Minister for Governorate Affairs: Saad Nayif al-Mishhin
Culture Minister: Nuri al-Rawi
Human Rights Minister: Nabil Mohammed Salim
Minister for Women's Affairs: Azhar al-Shaikhli
Al-Jaafari's transitional government, formed after January's elections, the first such democratic exercise in half a century, will be taking over from the interim administration led by Iyad Allawi.
Al-Jaafari's government, which will oversee the drafting by parliament of a new constitution, will remain in office until new elections in December.