Although Britain, France, Israel, Russia and the United States voted no, while China, India and Pakistan abstained, 123 UN members said they would hold the conference to draw up a legally binding nuclear ban treaty.
Japan, which is the only country to have suffered atomic attacks, voted against the talks, saying the lack of consensus over the negotiations could undermine progress on effective nuclear disarmament.
The countries leading the effort include Austria, Ireland, Mexico, Brazil, South Africa and Sweden.
The UN is to hold talks over a global nuclear weapons band
Hundreds of NGOs back their efforts, according to reports.
They say the threat of nuclear disaster is growing thanks to mounting tensions fanned by North Korea's atomic weapons program and an unpredictable new administration in Washington.
Swedish Foreign Minister Margot Wallstrom said: “I expect that this will take a long time, let's not be naive.
North Korean leader Kim Jong-Un (C) during a combat drill
"But it's very important in these days when you see more of this rhetoric, and also sort of power demonstrations, including threatening to use nuclear weapons.
"Quite a high number of countries are actually interested in saying we have to break the deadlock that has been on this issue for so many years.
"So it's also the expression of frustration."
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These countries are in the world's nuclear weapons club.
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While the major nuclear powers have made commitments to nuclear disarmament in recent years no actual progress has been made in working towards the goal set out in the 1968 Non-Proliferation Treaty.
Beatrice Fihn, director of the International Campaign to Abolish Nuclear Weapons, an international coalition of NGOs, said: "There was disappointment with the Obama administration, which made some pledges, but then ignored most of them.
“And now there are raised worries with the new US President.”
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No major powers have commented on the start of the talks so far, although the US ambassador to the UN, Nikki Haley, is expected to issue a statement on the sidelines of opening day.
US and French representatives explained their countries' opposition in October citing a need to make progress in stages, without disturbing the current strategic balance of weapons or jeopardising nuclear deterrence.
Ms Fihn compared such arguments to the logic of chain smokers. She said: "It's never the right time to quit.
South Koreans protest over Kim Jong-un's nuclear intentions
"But with the multipolar world, lots of countries feel like they don't have to wait for the superpowers to act.”
Tensions over a possible global conflict have been rising steadily in recent months.
Donald Trump, before he became US President, was sabre-rattling in January. He wrote in a tweet: “We will outmatch them at every pass and outlast them all.”
US President Donald Trump in the White House
Similarly, North Korea has been making overtures of aggression to both the US and various neighbours including South Korea and Japan.
A recent statement issued by the Korean People’s Army said that “the North Korean Army will deal deadly blows without prior warning any time”.
Tensions between the West and Russia have also been escalating with both sides carrying out high profile military exercises.
Recently Russian President Vladimir Putin moved 10,000 troops to the country’s borders while Spain sent tanks and armoured vehicles, along with 350 troops to Latvia in a bid to bolster Nato forces there.