Submitting his nomination papers ahead of the December 27 ballot, seen as the most closely fought vote in Kenya's history, Kibaki said his government had kept the reform promises it made when elected in 2002.

"We are a greater country today because of these changes," he said, highlighting the introduction of free primary education, the creation of thousands of jobs and what he called "major blows" dealt by the authorities against corruption.

"I am determined to build on the foundations we have laid in order to bring about even greater changes in Kenya," he said to the cheers of thousands of supporters at a Nairobi stadium.

The latest opinion poll has Kibaki trailing his main rival, Raila Odinga of the opposition Orange Democratic Movement (ODM), with 41 percent to Odinga's 45 percent.

A third candidate, Kalonzo Musyoka, has 15 percent.

Odinga, who was launching his party's manifesto on Thursday, paints himself as a champion of the poor and the alternative to a government he says has failed to deliver its 2002 election pledge of eliminating graft.

Kibaki has urged Kenyans to study his administration's record on development and economic growth against what his opponents did while they were in government -- which he says is little more than make unfulfilled promises.

Odinga and Musyoka were in Kibaki's cabinet before he fired them in 2005 after they fell out over a new draft constitution.