Created as yet another tool to prevent the spread of nuclear weapons, the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which was introduced 15 years ago on Saturday, has yet to come into force.

By banning all nuclear explosions -- thereby preventing states from testing new devices -- the global community hoped to introduce one more hurdle in the race to acquire weapons of mass destruction.

But rules on ratification have meant the text, which was adopted by the UN General Assembly on September 10, 1996, is still far from being implemented, and could well never be.

Under the so-called Annex 2 rules, the treaty will enter into force only when it has been signed and ratified by 44 key countries.

Among those that have yet to ratify the text are North Korea, Iran, Israel, Pakistan, India, China and the United States -- all states known to have or suspected of developing nuclear weapons.

In April 2009, US President Barack Obama raised hopes when he said he would seek Senate ratification of the CTBT. Washington has since put it on hold.

Indonesia also announced last year its intention to ratify the treaty "soon," with no sign yet of any movement.

"Current voluntary moratoriums on nuclear weapon tests are valuable, yet they are no substitute for a global ban," UN chief Ban Ki-moon warned in August, calling for progress on the CTBT.

In the meantime, a preparatory commission has been set up in Vienna for the future treaty organisation, the CTBTO, with monitoring stations all around the world to detect nuclear explosions.

The data recorded has also helped authorities put out earthquake and tsunami warnings, such as after the March 11 disaster in Japan.

The CTBT has so far been signed by 182 countries and ratified by 154.