More than 92 percent of voters in Congo Republic approved a change to the constitution that will allow President Denis Sassou Nguesso to run for a third consecutive term at elections next year, results of a referendum showed on Tuesday.

Turnout in the referendum held on Sunday was 72 percent, according to figures read by the electoral commission on radio. The opposition boycotted the poll and a senior opposition leader said it should be annulled due to low turnout.

"The smart thing would be to annul the referendum," opposition leader Pascal Tsaty Mabiala told Reuters by telephone.