For the United Nations, advocacy means promoting universal participation in existing international agreements or "instruments" that ban or limit the use of landmines. The most important of these agreements is the antipersonnel mine-ban treaty, which opened for signature in 1997.
The United Nations not only encourages all countries to participate in the treaty, but it also monitors the status of the treaty's implementation. In addition, the United Nations participates in and supports regular meetings of treaty member countries-or "states parties" to the treaty.
Another important instrument is the Convention on Certain Conventional Weapons and an amended Protocol II. This instrument focuses on the use of booby-traps and anti-tank and anti-vehicle mines. The United Nations provides technical and expert advice to meetings of the states parties to this instrument. In addition, the United Nations helps countries build their capacity to implement these instruments. 
For each of the 14 separate UN departments, agencies, programs and funds that support mine action, advocacy takes on a slightly different meaning or purpose. In some cases, more than one institution does similar advocacy work.
The UN Mine Action Service coordinates overall UN advocacy in support of the international legal instruments related to landmines and "explosive remnants of war" (which includes unexploded ordnance and abandoned explosive ordnance) and the rights of people affected by them. The organization also undertakes public information on the problems of landmines and explosive remnants of war and the global response to it. See also Cluster Munitions and Mine Action.
The UN Department of Disarmament Affairs' approach to advocacy includes assistance to states parties to comply with the terms of the antipersonnel mine-ban treaty and the Convention on Certain Conventional Weapons. The department also advocates for universal participation on the antipersonnel mine-ban treaty and the Convention on Certain Conventional Weapons.
UNICEF advocates for a total ban on antipersonnel landmines, the elimination of "weapons that have indiscriminate effects" on people, new legal instruments related to explosive remnants of war and the protection and promotion of the rights of women and children affected by armed conflict. In addition UNICEF advocates for the promotion of the rights of persons with disabilities, and the integration of victim assistance into public health, education and other social programs.
The UN Office of the Special Advisor on Gender Issues develops strategies and program to advance gender equality and the empowerment of women in all sectors, including mine action. The office's role is primarily in the areas of advocacy and policy support for "gender mainstreaming" in all of the United Nations' work.
The Office of the High Commissioner for Human Rights, in collaboration with the UN Mine Action Service and other institutions, is participating in the drafting of a new convention on human rights and dignity of persons with disabilities.
The UN High Commissioner for Refugees advocates is among the many UN institutions promoting a total ban on antipersonnel landmines.