"In common with other members of the international community, I have repeatedly stressed the importance of sustaining the cooperation among political parties on which the peace process was founded and which has brought it so far," Mr. Ban wrote.
The Nepali Congress, lead by former Prime Minister Girija Prasad Koirala, has chosen not to join the Maoist-led coalition Government. But the Secretary-General welcomed its pledge help draft the new Constitution and conclude the peace process.
He also praised the commitments made by current Prime Minister Pushpa Kamal Dahal - who goes by the name Prachanda - on his commitments to multi-party democracy and to protecting human rights.
Nepal, which in 2006 emerged from a decade-long civil war between Government and Maoist forces claiming 13,000 lives, abolished its 240-year-old monarchy in May and is now the Federal Democratic Republic of Nepal.
However, Mr. Ban lamented the fact that the "understandable" delays in forming the Government have not led to the "hoped-for progress" to allow the United Nations special political mission in the country, known as UNMIN, to wind down by its mandate's conclusion next January.
"The establishment of the special committee to oversee the integration and rehabilitation of Maoist army personnel is crucial in this respect," he said.
An agreement reached in late June by the Seven-Party Alliance call for integration and rehabilitation to wrap up within six months. "However, until the special committee begins its work, it is impossible to predict how soon it will be able to take key decisions and how long will be needed for their implementation," the report said, adding that there will be "substantial disagreements to be overcome."
The Secretary-General called on Nepal's Government to "move as rapidly as possible to create conditions conducive to the completion of UNMIN activities." The mission has already significantly its staffing level, but he expressed regret that the status-of-mission agreement still has yet to be signed by officials.
The new report also urged the international community to continue its support for the country to ensure that it successfully completes its peace process.
"While the main emphasis now should be on peacebuilding through economic and social development, and on the drafting of the new Constitution, experience in various countries has demonstrated the dangers of failing to address successfully the issue of former combatants and the risks that this can pose to durable stability."