* Former justice minister Ahoussou appointed PM
* Govt nearly unchanged, FinMin Diby retains post (Recasts with full government announcement)
By Loucoumane Coulibaly
ABIDJAN, March 13 (Reuters) - Ivory Coast President Alassane Ouattara kept a promise to a key ally on Tuesday by naming his new prime minister, Jeannot Kouadio Ahoussou, from the ranks of the PDCI party - the only major change in his newly announced government.
The PDCI party's backing helped Ouattara defeat former leader Laurent Gbagbo in a 2010 election.
Ahoussou, 61, was formerly justice minister and Ouattara's deputy campaign leader. He replaces Guillaume Soro, who on Monday was confirmed as the new head of the West African state's parliament.
Ouattara beat Gbagbo in a November 2010 election after securing the backing of the PDCI presidential candidate Henri Konan Bedie in a second round run-off.
Gbagbo refused to accept defeat, however, triggering a four-month conflict until he was finally ousted with the help of U.N. and French troops. Gbagbo's FPI party has since criticized Ouattara for stiffling political dissent, and boycotted parliamentary elections in December.
No FPI party members are represented in the government.
Involved in politics since the 1970s, Ahoussou was one of the key players in the Ivorian peace process following a 2002-3 civil war that eventually culminated in the 2010 elections. He has been an adviser to Bedie since 2005.
Loma Cisse Mattou replaces Ahoussou as justice minister delegate, Amadou Gon Coulibaly, Secretary General of the Presidency told a news conference, adding no other posts had in the government had changed.
Finance Minister Charles Koffi Diby's retention of his post will likely mitigate concern Ivory Coast may change the payment schedule on its 2032 $2.3 billion bond which went into default after the disputed November poll.
Analysts said the transition since Soro resigned last week had also reinforced optimism among investors.
"The smooth and pre-arranged power shift that followed Guillaume Soro's resignation last week certainly suggests that risks to Cote d'Ivoire's political outlook are marginal," said Samir Gadio, emerging markets strategist at Standard Bank.
Ouattara retains his post as defense minister, one of few African presidents holding the defense portfolio. (Writing by Mark John and Richard Valdmanis; Editing by Robert Woodward/Patrick Graham)