Opposition parties led by two former presidents will try to shake the grip of Ivory Coast President Alassane Ouattara in a parliamentary election on Saturday, five months after a presidential vote that led to deadly unrest.

Former President Henri Konan Bedie's Democratic Party of Ivory Coast (PDCI) and former President Laurent Gbagbo's Ivorian Popular Front (FPI) both boycotted the presidential election last year, which Ouattara won in a landslide.

Eighty-five people died in violence around that election, although the situation has since cooled.

A faction of FPI loyal to Gbagbo and PDCI are now fielding a joint list of candidates against Ouattara's Rally of Houphouëtists for Democracy and Peace (RHDP). With no reliable public opinions polls available, their prospects are difficult to forecast.

Clear control of parliament would strengthen Ouattara's hand to pursue an agenda based on attracting foreign investment and cutting red tape during his third term, while the vote could be decisive for the opposition to show it remains relevant.

"Their credibility is at stake because in the event of defeat, the opposition will be reduced to nothing, and risk dividing further, and this can only benefit the party in power," said Ousmane Zina, a political analyst.

Other opposition figures, such as former Prime Minister Pascal Affi N'Guessan who leads another FPI faction, are also standing, outside the main joint list.

The PDCI, which dominated politics in Ivory Coast from the 1940s until Bedie was overthrown as president in 1999, backed Ouattara for years but split with him in 2018.

Gbagbo's FPI faction will be fielding candidates for the first time since 2011, when Gbagbo was sent to The Hague to face war crimes charges after a brief civil war sparked by his refusal to concede an election defeat to Ouattara. Gbagbo, acquitted of war crimes by the International Criminal Court in 2019, is expected to return to the country soon.

"For us, this legislative election must be the beginning of the reconquest of power, and the return of the opposition to power," said Gbagbo's 50-year old son Michel, a candidate.

Patrick Achi, Ouattara's chief of staff, told a campaign meeting in the southeast of the country that the election was vital.

"It must confirm the presidential election victory and give President Ouattara the parliamentary majority he needs to carry out his economic and social policies during this term."