Addis Ababa - South Sudanese President Salva Kiir has signed a peace deal aimed to end civil war, but a list of government reservations seen on Thursday undermines fundamental pillars of the accord.

The 16 reservations, listed in a document handed out to diplomats and regional leaders after the signing on Wednesday, includes major issues over power-sharing with rebels.

The UN Security Council has given Kiir until September 1 to get fully behind the agreement or face possible sanctions, and the United States has circulated a draft resolution that would impose an arms embargo and targeted sanctions on those who undermine peace efforts.

The deal signed gives the rebels the post of first vice president, which means that rebel chief Riek Machar would likely return to the job from which he was sacked in July 2013, an event which put the country on the path to war later that year.

The 12-page document however calls this a "humiliation" and a "reward for rebellion", and insists the post of first vice-president must be on equal footing with the current vice-president, whose post remains.

It also opposes rebels nominating two powerful governor posts in the battleground state of Unity and Upper Nile, the main oil-producing states.

Transitional government of national unity

"Handing over the two states to the rebels is a reward that will provoke rebellions and divisions," the document reads.

It objects to the powers of the foreign-led Monitoring and Evaluation Commission - the body that will police the implementation of the deal - that will report to the international community.

"For South Sudanese, this simply means taking over the sovereignty and the hard won independence of their country," the document reads.

Another objection is the demilitarisation of the capital, with no troops allowed within a 25km radius of Juba.

"The army has the duty responsibility to protect the nation, its people and its leadership," the document reads. "Regardless of any military logic, the fact that they are being relocated because of the rebels is provocative and may cause instability."

Under the deal, a "transitional government of national unity" will take office 90 days after the signing of the deal, and govern for 30 months.

But Kiir has rejected a proposed gradual process of integration of the army and rebels into a new joint force, demanding it be done within three months.

"The transitional period should start with one national army, not two armies," the document reads.