While nuclear-armed powers have not signed up to the treaty, its proponents hold out hope that it will nonetheless prove to be more than symbolic and have a gradual deterrent effect, calling the achievement historic.

The 75th anniversary of the nuclear bomb attacks on Nagasaki and Hiroshima, marked in August, saw a wave of countries ratify the treaty in recent months.

They have included Nigeria, Malaysia, Ireland, Malta and Tuvalu.

Thailand, Mexico, South Africa, Bangladesh, New Zealand, Vietnam and the Vatican are among the countries that had already ratified the treaty.

It is now expected to enter into force in January 2021.

"Today is a victory for humanity, and a promise of a safer future," Peter Maurer, president of the International Committee of the Red Cross (ICRC), said in a statement.

Other NGOs also welcomed the news, including the International Campaign to Abolish Nuclear Weapons (ICAN), a coalition that won the 2017 Nobel Peace Prize for its key role in bringing the treaty to fruition.

"Honduras just ratified the Treaty as the 50th state, triggering entry into force and making history," ICAN said in a tweet.

- 'A new chapter' -

The Treaty on the Prohibition of Nuclear Weapons -- which bans the use, development, production, testing, stationing, stockpiling and threat of use of such weapons -- was adopted by the UN General Assembly in July 2017 with the approval of 122 countries.

Eighty-four states have since signed it, though not all have ratified the text.

The clutch of nuclear-armed states, including the United States, Britain, France, China and Russia, have not signed the treaty.

However, campaigners hope that it coming into force will have the same impact as previous international treaties on landmines and cluster munitions, bringing a stigma to their stockpiling and use, and thereby a change in behavior even in countries that did not sign up.

Nuclear-armed states argue their arsenals serve as a deterrent and say they remain committed to the nuclear Non-Proliferation Treaty, which seeks to prevent the spread of nuclear weapons.

ICAN said in a statement that "we can expect companies to stop producing nuclear weapons and financial institutions to stop investing in nuclear weapon producing companies."

The coalition's executive director Beatrice Fihn called it "a new chapter for nuclear disarmament."

"Decades of activism have achieved what many said was impossible: nuclear weapons are banned."