The delay in its unveiling was apparently caused by the arrest on Saturday of Seif al-Islam Kadhafi, the prominent son and onetime heir-apparent of the slain dictator.
Osama Juili, commander of the Zintan fighters who arrested Seif, got the defence ministry, while the interior ministry went to Fawzi Abdelali from the former rebel town of Misrata, whose fighters captured Kadhafi in October.
Kib chose Ashur bin Khayyal, Libya's envoy to Canada under the Kadhafi regime who joined the opposition in the 1990s, to head the foreign ministry, while Abdelrahman bin Yazza -- a former official at Italy's energy major ENI -- becomes interim oil and gas minister.
Lawyer Fethi Tarbel, whose brief arrest on February 15 was the spark that lit the popular uprising against Kadhafi's regime in the eastern city of Benghazi, was named minister of youth and sport.
Kib will head a 24-member government which will include such portfolios as the ministry of martyrs, wounded and missing people, and a ministry of civilian society.
The National Transitional Council gave the new government its vote of confidence, NTC vice chairman and official spokesman Abdel Hafiz Ghoga said.
The NTC, whose rebel fighters backed by NATO air support toppled Kadhafi in October, chose Kib, a little-known university professor from Tripoli, on October 31 to form an interim government.
Having declared the country's "liberation" three days after the October 20 capture and killing of Kadhafi, the NTC has launched a roadmap to a new Libya with a 20-month countdown to a general election.
Under the roadmap, the NTC is to hand over power to a 200-member elected assembly within eight months which in turn has two months to name a premier whose government must form a commission to draw up a constitution.
The NTC published its roadmap in August and is due to step down once the congress holds its first session.
Kib had said the new government would be formed of technocrats, although he came under pressure from Libya's tribes and numerous armed factions which had also demanded a role.
An NTC statement distributed after Kib unveiled his government spelled out the tasks expected to be accomplished by the cabinet, with the "restoration of normal life."
"This provisional government aims to achieve the following: first security, stability and restoration of normal life by providing basic social services, the return of children to their schools and the payment of (overdue) salaries," it said.
It also pledged to establish "justice which guarantees the rights of individuals who have been harmed over the past 42 years and also which guarantees those accused a fair trial."
The new government, the statement said, will help efforts by the NTC "to achieve national reconciliation" in Libya.
It will also strive to rebuild the army and the security forces and promote "the integration of interested citizens into these institutions."
Hours before Kib's news conference, the Zintan military council whose fighters captured Seif al-Islam issued a statement denying that the defence ministry would be given to Juili as a bribe because his men allegedly refused to hand over Kadhafi's son to the NTC.
"The Zintan military council denies the information published by media according to which Zintan is involved in blackmail regarding Seif al-Islam in return for a cabinet post," a statement said.
It said Seif was being held in Zintan "for security reasons in agreement with the National Transitional Council."
In Geneva, the International Committee of the Red Cross said two of its representatives met Seif on Tuesday for several hours in Zintan.
"He appeared to be in good health," spokesman Steven Anderson told AFP, adding: "The organisation's findings are being shared with the detaining authorities only."