The Joint Monitoring and Evaluation Commission (JMEC) said in a statement released in Juba that it welcomed the signing of the outstanding issues on governance between parties to the conflict on Sunday.
"This most recent signing strengthens efforts to revitalize the 2015 Agreement on the Resolution of the Conflict in South Sudan (ARCSS), and is expected to lead to the achievement of an inclusive, comprehensive peace, restore security, stability and promote national reconciliation in the Republic of South Sudan," it said.
The peace monitors also called on the parties to commit to an honest and effective implementation of the revitalized agreement going forward.
"Undoubtedly, the signing comes as a ray of hope for the people of South Sudan who have witnessed the devastation of war for far too long," it added.
President Salva Kiir and the main opposition leader Riek Machar of the Sudan People's Liberation Movement-In Opposition (SPLA-IO) and other opposition groups signed the peace agreement mediated by the Sudanese President Omar Al-Bashir under the auspices of the East African bloc IGAD.
The agreement will see Machar return to his former First Vice President post and other four vice presidents will be appointed in the transitional unity government.
The transitional Parliament will comprise 550 lawmakers, 332 from Kiir's side and 128 from Machar's faction and others from the nine opposition political parties.
"Following the signing, the commission reminds the parties of the need to work together in good faith as efforts continue to finalize the revitalization of the remaining Chapters of the ACRSS with consequential amendments," it said.
President Kiir and rebel leader Machar agreed to the 2015 peace agreement but it was weakened after the parties clashed in July 2016 forcing Machar to flee Juba into exile.
The Khartoum peace deal is seen as the last chance at bringing peace to South Sudan ending more than four years of brutal conflict and displacements.
JMEC also said it will be working with all parties to ensure the full implementation of the revitalized peace agreement.
It lauded the leadership of the IGAD, African Union (AU), United Nations (UN), and the international community and all partners for their sustained efforts to ensure a lasting peace is achieved in the country.
South Sudan descended into civil war in late 2013, and the conflict has created one of the fastest growing refugee crises in the world.The UN estimates that about 4 million South Sudanese have been displaced internally and externally.