Survivors of the 1945 atomic bombings of Hiroshima and Nagasaki have expressed hopes that US president-elect Joe Biden will promote nuclear disarmament.

Speaking to NHK on Sunday, the acting leader of the Hiroshima branch of the Japan Confederation of A- and H-bomb Sufferers Organizations, Mimaki Toshiyuki, offered congratulations on Biden's projected win.

Survivors of the 1945 atomic bombings of Hiroshima and Nagasaki and peace groups are launching a signature campaign to urge the Japanese government to ratify a UN treaty banning nuclear weapons.

The Treaty on the Prohibition of Nuclear Weapons will enter into force in January after reaching the necessary 50 ratifications earlier this month. But Japan is among the countries that have not signed the treaty. Nuclear powers, including the United States, Russia and China, have not joined the pact.

Prime Minister Abe Shinzo has pledged continued support for "hibakusha," or survivors of the 1945 atomic bombing, following an appeal by the city and prefecture of Hiroshima of a ruling on so-called "black rain."

Last month a district court in Hiroshima recognized people who were exposed to the radioactive rain immediately after the bombing as "hibakusha."