A South Sudan spokesman says President Salva Kiir may sign a peace deal with rebels on Wednesday, more than a week after refusing to do so.

Ateny Wek Ateny said Tuesday that Kiir will first express "reservations" about the agreement with rebel leader Riek Machar at a summit with regional leaders in the capital, Juba.

Kiir is unhappy about the agreement's demands that Juba be demilitarized, the rebels will appoint two state governors, and a foreigner will head a monitoring commission, he said.

Last Monday Machar signed the deal, designed by the regional bloc known as IGAD and backed by the African Union, western nations and China. Kiir said he needed to consult before he could sign the agreement. South Sudan has been at war since December 2013.