UPDATE 6-"Yes" voters take early lead in Kenya referendum

* New law meant to address graft, tribalism, land issues

* Kenyans vote peacefully in constitution referendum

* "No" camp alleges vote rigging

(Adds 'No' camp claims vote rigged, minister quote, observers)

By Duncan Miriri

NAIROBI, Aug 4 (Reuters) - Partial results showed two-thirds of Kenyans voted in favour of a new constitution on Wednesday in a peaceful poll that could reshape the politics of east Africa's largest economy after years of disputed, violent elections.

The constitutional changes are seen as important to avoid a repeat of the post-election tribal bloodshed in early 2008 that killed 1,300 people and pushed the country of about 40 million people to the brink of anarchy.

They address the corruption, political patronage, land grabbing and tribalism which have plagued Kenya since it won independence in 1963. The changes allow for greater checks on presidential powers, more devolution to grassroots administrations and an increase in civil liberties.

"I have come to vote for the new constitution which will guarantee me security in my farm where I was displaced in 2007 during clashes," said Milkah Gathoni Njoroge, who was born in 1919. "I am living with my family in Nakuru town. If the constitution passes, I will return to my land."