Suresh Chalise, an aide to the Nepalese prime minister, said Girija Prasad Koirala wrote to Kofi Annan asking for UN help.
Monitoring arms is seen as crucial to a free and fair vote as the guerrillas control large swathes of the Himalayan nation and are known to enforce their writ through threats.
Chalise said: "We have requested the United Nations to assist the government of Nepal in the peace process.”
Koirala, appointed after King Gyanendra gave in to pro-democracy protests in April, and Maoist chief Prachanda last month agreed to include the rebels in an interim government to oversee elections for a special assembly to prepare a new constitution and decide the future of monarchy.
The interim government and the Maoists also agreed to seek UN help to monitor and manage their armies and arms ahead of the vote.
No date has been set for the polls.
The vote and the new constitution are seen as a first step towards ending a decade-old Maoist insurgency that has killed more than 13,000 people since 1996.