Geneva  - The end of the Cold War does not mean the nuclear arms race has ended, the last president of the Soviet Union warned Monday.

Speaking at a conference on nuclear disarmament at the United Nations headquarters in Geneva, Mikhail Gorbachev said there remained multiple obstacles to a nuclear-free world.

"The only way to eliminate nuclear danger is to eliminate nuclear weapons," said Gorbachev.

"There is a real threat of a real arms race and 'weaponization' of outer space," he told a forum attending the "Resetting the Nuclear Disarmament Agenda" seminar.

The UN believes there are more than 23,000 nuclear weapons in existence today, alongside an unknown quantity of fissile material that can be used to make bombs. Global military spending is estimated to be worth over 1.3 trillion dollars.

"The world is over-armed and peace is under-funded," said UN Secretary General Ban Ki-moon at the conference.

Speaking about the proliferation of nuclear weapons in the world, Gorbachev said that "absolute security for some means insecurity for all others."

Gorbachev signed the Strategic Arms Reduction Treaty (START) with then president of the United States George H. W. Bush, just before the USSR collapsed. That agreement limited the amount of nuclear arms each side could maintain, and is set to expire later this year.

The current US administration is in the process of negotiating a follow up to START with Moscow.

Teams from both sides have been meeting in Geneva in attempts to hammer out a deal, the presidents of both sides have discussed the issue and US Secretary of State Hillary Rodham Clinton will be in Moscow next week, with the nuclear matter expected to be high on the agenda.

US President Barack Obama said earlier this year that he would strive for a world free of nuclear weapons, even if it was a process that took generations to complete.

Last month, Obama headed a UN Security Council meet on nuclear disarmament, the first such discussion of its kind, attended by heads of states of the world's major powers.  dpa