Ivory Coast police fired tear gas and arrested several political leaders Thursday at a protest in the capital Abidjan against a proposed new constitution,

The controversial constitution which changes contentious rules on presidential eligibility will be put to a referendum on October 29.

A vast deployment of anti-riot police greeted protesters carrying banners saying "No to the Ouattara monarchy", referring to President Alassane Ouattara who says the amendments will help end years of instability and conflict in the world's top cocoa producing nation.

Police fired tear gas at the crowd after warning them that they did not have permission for their protest.

Several opposition political leaders were also arrested including Aboudramane Sangare, a senior figure in the Ivorian Popular Front (FPI) and Mamadou Koulibaly, former president of the national assembly.

"This is Ouattara's democracy," said Koulibaly after being loaded into a police troop carrier.

The draft constitution, which parliament overwhelmingly approved last week, changes the rules on presidential eligibility and establishes a senate.

Critically, it would lift the current requirement that both parents of a presidential candidate must have been born in Ivory Coast.

Ouattara's father was born in neighbouring Burkina Faso and his rival in the 2010 election Laurent Gbagbo, refused to cede power over the issue after losing his re-election bid, triggering widespread violence.

Ivory Coast's main opposition coalition last week called on voters to boycott the referendum.

"We are on the path to boycott," said Pascal Affi Nguessan, president of the FPI founded by Gbagbo, during the protest Thursday.