"This is a crucial stage in the implementation of the agreement on monitoring the management of arms and armies," said Ian Martin, special representative of the UN Secretary-General in Nepal and head of the UN Mission in Nepal (UNMIN).
The move is the second stage in the registration of Maoist arms and armies, after the first phase in April when over 2,855 weapons were registered under the supervision of UNMIN monitors, said officials.
All the weapons have been stored in seven Maoist army main cantonment sites and locked in storage containers secured by a single lock provided by UNMIN.
After nearly a decade of armed conflict that killed over 14,000 people and internally displaced nearly 200,000 persons, a truce was finally reached between the government and Maoist insurgents in November 2006.
One of the key agreements of the deal was the management of arms and armies on both sides.
Martin said the process was crucial because the Maoists would fulfil their commitment to discharge underage soldiers.
Local child rights activists have often accused Maoist leaders of not releasing child soldiers - something the former rebels have consistently denied.
"UNICEF [the UN Children's Agency] and its partners will be making arrangements for the re-integration of those found to be minors," said Martin.
Local child rights non-governmental organisations (NGOs) estimate that up to 30 percent of the 30,000 Maoist combatants are minors.
However, the actual number will be determined after the UN verification process this week led by United Nations Development Programme (UNDP) registration personnel and UNICEF child protection officers, said UNMIN officials.
UNMIN officials said the main objective of its presence in Nepal was to create a free and fair atmosphere for elections tentatively planned for November this year.
One way to do this is by disarming former Maoist rebels and government forces. To ensure that the peace agreement is implemented properly, UNMIN, the government and Maoists have formed Joint Monitoring Teams (JTMs), each of which has representatives from all these three parties.