They are built to explode above the ground, releasing thousands of bomblets intended to detonate on impact.
But a series of studies have shown that as many as 40 per cent of the bomblets fail to go off immediately and instead only go off much later when disturbed by civilians.
For example, according to conference organisers, Israel's use of cluster bombs during the 2006 war in Lebanon led to more than 200 civilian casualties in the 12 months following the ceasefire.
"What we're trying to prohibit is those cluster munitions that cause unacceptable harm to civilians"
New Zealand Disarmament Ambassador
"What we're trying to prohibit is those cluster munitions that cause unacceptable harm to civilians," Don Mackay, the conference chairman and New Zealand's disarmament ambassador, told The Associated Press.
Opening the conference on Monday New Zealand's defence minister said that protecting civilians was a key element of the proposed treaty.
"The challenge before us is to build agreement among a sufficient mass of countries, including those who possess cluster munitions, to form a legally binding treaty to stop unacceptable harm to civilians," Phil Goff told delegates.
New Zealand is one of six governments leading the process, along with Austria, Ireland, Mexico, Norway and Peru.
The move to ban the controversial weapons has been backed by 83 nations, but key countries such as China, Russia and the United States - the main manufacturers of the munitions - remain opposed to an outright ban.
|This two-year-old Palestinian girl was injured |
last week by an Israeli cluster bomb [AFP]
They have not joined the process and have not sent observers to the Wellington conference.
The conference has been organised by the Cluster Munitions Coalition (CMC), a global network of 200 civil society organisations including leaders from the Nobel Peace Prize-winning International Campaign to Ban Landmines.
"After a year of remarkable progress to save lives, this is the moment of truth when countries must show their resolve and commit to negotiate the new treaty," Thomas Nash, the coalition's co-ordinator, told the conference.
According to the CMC, France, Germany, Japan and the UK have been stepping up diplomatic pressure to weaken the draft treaty by excluding certain weapons, including a transition period and allowing the use of cluster bombs in joint military operations with countries that do not sign the treaty.
But Steve Goose, a spokesman for US-based Human Rights Watch, said countries that were serious about saving lives would support strong measures.
"The treaty must not be weakened to pander to the interest of users, producers and stockpilers," he said.