Former United Nations Secretary General Kofi Annan has called on Kenya to speed up reforms promised after post-election violence in early 2008, BBC reported.
Speaking at the start of a three-day visit, he said Kenyans expected more from the coalition government.
On Monday Mr Annan will meet Kenya's President Mwai Kibaki and Prime Minister Raila Odinga.
He brought the men together in a peace deal last year to end violence in which more than 1,300 people died.
As part of the deal, politicians promised to carry out major reforms in the judiciary and the police force as well as electoral and land reform.
Mr Annan, who was instrumental in pulling Kenya back from the brink of civil war, made it clear that so far the pace of reform has been too slow.
He said the people of Kenya expected more concrete action to end impunity for the perpetrators of violence and to combat corruption.
Mr Annan said that despite the slow progress, the much-needed reforms were still possible.
He said it was vital that the reforms were carried out well ahead of elections in 2012.
After meeting President Kibaki and Mr Odinga on Monday, Mr Annan will hold talks with civic groups and business leaders.
Politicians are likely to say they are doing their best, but most Kenyans feel very little progress has been made especially in the fight to end impunity.
Several politicians have been accused of instigating the violence.
The pursuit of justice has been so slow that the International Criminal Court (ICC) has stepped in, saying it will prosecute key instigators of the violence.
Bringing those people to justice could reopen some political rifts.
But many Kenyans feel it is a risk worth taking to help end the deeply rooted culture of impunity.