"Our people are now in the process of reconciliation," President Mwai Kibaki said at the ceremony, nearly four months after the December 27 poll that triggered what was arguably the darkest period in Kenya's post-independence history.

"We can and must bring the cycle of violence to an end."

The 41-member cabinet -- Kenya's largest and costliest ever -- was sworn in at the official State House residence of Kibaki, who split government posts with the party of his closest election challenger, new Prime Minister Raila Odinga.

The two men met secretly at the weekend to break a six-week deadlock over forming the coalition, the cornerstone of a power-sharing deal agreed in February.

"We have been to hell and back. Never again in our history must we return to those times," Odinga said, promising that the coalition government's priority would be to help the 300,000 people uprooted from their homes during the crisis.

More than 1,200 people died in tribally-tinged clashes.

The establishment of the new cabinet has brought relief to traumatised Kenyans and nervous investors watching for signs of lasting peace in east Africa's biggest economy.

The shilling currency and local stock market have already rebounded from sharp falls when the country erupted into riots and ethnic killings for more than a month.

But there are doubts among Kenyans and foreign analysts over whether the government can stick together with so many diverse groups, interests and personalities now in it.

The cabinet is supposed to steer the redrafting of a new constitution within 12 months, to help address long-simmering issues of land, wealth and power that fuelled the crisis.

But many in Kenya expect it to descend into bickering and concentrate more on self-enrichment than major reforms.

"It's not going to be united," housewife Unia Isaac, 32, said. "It's the common man who is going to lose a lot."

IN THE FAMILY

The inauguration makes Odinga only the second prime minister in Kenyan history. Founding president Jomo Kenyatta was prime minister for the year after independence from Britain in 1963.

Former U.N. chief Kofi Annan, who mediated the deal, attended Thursday's ceremony, along with Uganda's President Yoweri Museveni and Burundi's President Pierre Nkurunziza.

"Don't believe that now we have a government all is resolved and we can relax," Annan said.

"Peace is precious. Let's not lose it again."

Museveni echoed that message: "Congratulations for treating the disease you had. Now you have a cure, don't joke with it."

For Odinga, it marks a bittersweet ascendancy to a top job. His father, independence figure Jaramogi Oginga Odinga, was vice president under Kenyatta but the two fell out badly.

Showing how little the political cast of characters and dynasties have changed since then, Kenyatta's son Uhuru was sworn in as one of two deputy prime ministers under Odinga.

For years, the former political prisoner Odinga has sought to be Kenya's president and came within a few hundred thousand votes in the December election, which Odinga said Kibaki stole.

The ensuing violence and pictures of machete-wielding youths who for weeks paralysed parts of Kenya seriously harmed its image as the stable, prosperous anchor of turbulent east Africa.

Enormous international and local pressure brought the two sides to a deal to stem the violence, but still-raw rivalries kept the cabinet from being named for weeks.

Critics of the size of the cabinet say it will cost $1 billion a year -- about 5 percent of Kenya's GDP -- to maintain, between salaries for 41 ministers and 50 assistant ministers, plus large cars, bodyguards and support staff.