Mass rival rallies have been held in the Kenyan capital Nairobi ahead of Monday's vote on a new constitution.
The banana is the symbol for the Yes camp
In recent weeks, campaigning had been marred by violence, with nine deaths.
Riot police were out in force on Saturday and a buffer zone was set up to keep the rallies apart. But the unrest many feared did not materialise.
The constitution will boost the president's powers and maintain his powers of patronage, but critics say Kenya needs more checks and balances.
President Mwai Kibaki argues that the constitution would create a balance of power between president, parliament and regional assemblies.
Mr Kibaki is leading the Yes campaign under the symbol of a banana, while the opposition camp is using an orange.
The symbols were chosen by Kenya's electoral commission to aid illiterate voters.
According to Reuters news agency, the opposition camp attracted 30,000 supporters to its rally in the Nyayo stadium, while about 12,000 attended the government's meeting a short distance away in Uhuru Park.
The orange is the symbol of the campaign against the constitution
One of the president's allies, Local Government Minister Musikari Kombo said Monday's referendum was a vote "between those who like peace and those who like violence."
His comments were echoed by another Kibaki ally, Norman Nyagah, who accused the No camp of wanting to foment unrest to thwart government efforts to get the charter endorsed.
For the opponents of the constitution, Roads Minister Raila Odinga accused constitution supporters of planning to incite people so that they could rig the vote.
Another government minister, Kalonzo Musyoka, predicted an easy victory for the No camp. "If they rig, then you'll have Ukraine here," he said in a reference to people-power demonstrations.