NAIROBI (Reuters) - Former U.N. chief Kofi Annan warned Kenya on Friday that failure to push through political reforms aimed at healing deep ethnic rifts could undermine the recovery in east Africa's largest economy.

Annan led weeks of negotiations that ended political and ethnic clashes after a disputed presidential poll in December 2007, shattering Kenya's image as the region's most stable business hub.

"The economic recovery that has started to take place since the post election violence ... can only be sustained if genuine reforms continue to be implemented and there is cohesion in the government," Annan told reporters during a visit to Kenya.

Kenya's economy is expected to grow by about 4 percent this year, up from an estimated 2-2.5 percent last year. The post-election turmoil, drought and the global financial crisis cut growth from 7 percent in 2007 to 1.7 percent in 2008.

President Mwai Kibaki and his prime minister, Raila Odinga, arch rivals in the last poll, agreed to share power after 1,300 Kenyans died and 300,000 were uprooted during weeks of bloodletting in early 2008. Anan met both men during his visit.

Under the terms of the deal signed between Odinga and Kibaki in 2008, the country was supposed to institute legal, political, social and economic reforms to promote stability and peace.

The promised reforms include writing of a new constitution, changes in the courts and police force, as well as land reforms.

Annan noted progress with the constitution, a draft of which is being debated in parliament, and the formation of a new electoral body, but singled out judicial reforms as one area where the government can move faster.

FOCUS ON 2012 VOTE

But political analysts say bitter divisions between the main parties in power and rivalries within each side have slowed the pace of reform, with many politicians more concerned about the next presidential vote in 2012.

Annan said there had been a failure to address meaningfully the issue of impunity and corruption.

The International Criminal Court (ICC) was set to announce next week whether it will proceed with cases against a number of people suspected of involvement in the violence, thought to include government ministers and prominent businessmen, he said.

Annan handed over a list of names to ICC prosecutors after Kenyan legislators stalled on setting up a local tribunal.

"Since that (ICC) is a process that has been initiated, most of us are paying attention to that," said Annan.

"It will be up to the government to decide when it introduces the bill for the local tribunal, if it will. The ball is still in their court," he said.

Annan voiced particular concern about reports of intimidation of witnesses and human rights defenders.

He urged parliament to pass swiftly a hotly debated constitutional bill that has come unstuck over the division of executive power.

"The longer the reforms take the more complicated it will get. The elections and the politics will begin to cast a long shadow," he said.