Voting appears to have passed off peacefully, with none of the violence that marred December 2007's election.

The referendum was part of a deal to bring that conflict to an end - more than 1,000 people died in the clashes.

The new constitution gives citizens a new bill of rights and paves the way for land reform.

With 67% of the ballots counted, more than four million voters were in favour of the new charter. Around 2.1 million had rejected the reforms.

However, the BBC's Peter Greste in Kenya says that there has been a strong "No" vote in the Rift Valley province, which saw the worst of the post-election violence in 2007 and 2008.

He says the result in this province is a blow to the idea that the new constitution could help to create a national consensus.
But William Ruto, a cabinet minister based in the Rift Valley who led the "No" camp, said he would accept the outcome of the poll.

Mr Ruto, who has ambitions to run for president in the 2012 elections, had opposed clauses about abortion and land reform.
Those in favour of the document say that for the first time it introduces a sensible approach to land reform by stating that land acquired illegally can be repossessed.

Supporters of the new constitution include both the president and prime minister, who stood against each other in 2007.