About 560 delegates from 122 countries have converged on Wellington for the conference which aims to draft a treaty text, to be negotiated in Dublin, Ireland, in May.
The attempt to achieve a treaty, known as the Oslo Process, was started last year by New Zealand and six other countries.
Opening the conference, Disarmament Minister Phil Goff said a strong declaration on cluster bombs at the conference would mark a pivotal step in getting the weapons banned.
More than half of the 76 states in the world that stockpile cluster munitions are taking part in the negotiations, along with a majority of the weapon producers.
However, major producers such as the US, Russia, China and Pakistan have not joined the process and have no observers at the conference.
Cluster bombs are built to explode above the ground, releasing thousands of bomblets primed to detonate on impact. But combat statistics show between 10 percent and 40 percent fail to go off and lie primed in the target area to kill and injure civilians.
UNICEF deputy executive director Hilde Frafjord Johnson, speaking on behalf of 14 United Nations entities that form the United Nations Mine Action Team, said the UN wanted cluster bombs banned.
She said the weapons had a horrendous humanitarian, development and human rights impact.
Ms Johnson said the extensive use of cluster munitions in southern Lebanon in 2006 was a tragic reminder of how they caused death and serious injury of civilians.
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"Sometimes, the presence of unexploded sub-munitions forced populations out of their homes and prevented those already displaced from returning home to rebuild their lives and communities."
Ms Johnson spoke of 12-year-old Hassan Hemadi, who in 2006 picked up an object outside his home in southern Lebanon while he was watering the family garden.
"'I saw a metal object,"' Johnson said, quoting Hemadi.
"'I did not know what it was and so I picked it up. I started playing with the ribbon on the end, twirling it around. Then I don't know what happened, it exploded. Now I have lost the fingers on my hand."
Mr Goff urged delegates to tackle difficult areas to come up with a declaration that provided a "solid foundation" for the May negotiations.
"It is now time to put the fence at the top of the cliff, and not simply be the ambulance at the bottom."
"We need to eliminate the use of cluster munitions where they have an unacceptable effect on civilian populations," Mr Goff said.
But Amnesty International spokeswoman Margaret Taylor said any declaration that fell short of calling for a complete ban on the destructive weapons would be a failure.
Ms Taylor said cluster bombs, which could be fired, launched or dropped by aircraft or artillery, were more lethal than landmines yet there was no international treaty on their use.
Amnesty opposed the manufacture, stockpiling, transfer and use of cluster munitions.
© 2008 TV 3 News New Zealand