Judge Rita Makarau, head of the electoral commission, said Sunday the low estimate came from early returns from the nation's 9,400 polling stations.
In its preliminary report of the March 16 referendum, the Southern African Development Community’s Electoral Observer Mission commended Zimbabwe for conducting what it called a peaceful constitutional referendum.
Head of the mission, Bernard Membe, said despite minor challenges, the referendum was a success and credible.
The SADC observer team commended ZEC for conducting the referendum procedurally, particularly the counting and collation of results at polling stations.
The team also urged the nation to maintain the peace that prevailed during the referendum as the country prepares for harmonised elections.
It recommended, among other issues, for a timeous availability of election funds and continuous voter education.