Seven children are among 17 civilians killed or injured in incidents connected to unexploded ordnance left behind on New Zealand’s firing ranges, Stuff Circuit's documentary Life + Limb reveals.

Former Prime Minister Helen Clark says it is "reprehensible" that unexploded ordnance left behind on firing ranges in Afghanistan is killing people.

"New Zealand has at the very least a moral responsibility to remove any toxic remnants of war for which it was responsible," she told Stuff Circuit.

"New Zealand could be a leader in this area by accepting responsibility for cleaning up the toxic mess it has left."

ROSA WOODS/STUFF Former Prime Minister Helen Clark made the decision to deploy soldiers to Afghanistan in 2003.

Clark, who headed the United Nations Development Programme from 2009-2017, was responding to the Stuff Circuit documentary Life + Limb.

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The documentary revealed that 17 civilians had been killed and injured in nine separate incidents on firing ranges used by New Zealand soldiers while they were deployed to the central Afghan province of Bamyan.

SUPPLIED Five of the seven children killed in an explosion caused by a device left behind on a New Zealand firing range in Afghanistan, including (left to right) Hussain Khudabakhsh, Hussain Bakhsh Mohammad, and Amina Nowruz.

Among the dead are seven children killed when one of them picked up a device and carried it back to a field near their village. It exploded when they were playing with it.

An eighth child survived the explosion but was not found for three days - he'd been hiding, traumatised, in a cave.

The United Nations says New Zealand is responsible for the nine incidents, and is calling for the ranges to be cleared immediately.

PHIL JOHNSON/STUFF CIRCUIT A boy crosses the range with a load of brushwood. Even though they know it's dangerous, the boys say they need to collect the wood for cooking and heating.

The New Zealand Defence Force has refused to be interviewed, instead issuing a statement which seeks to diminish its responsibility, implying the incidents could be the fault of Russian or American devices left prior to New Zealand's arrival in Bamyan.

Nevertheless, it says it has set aside $10 million to clean up the ranges, though locals, who have been complaining about the danger on the ranges since at least 2013, query why it is taking so long.

Clark - who made the decision to deploy soldiers to Afghanistan in 2003, a deployment which lasted until 2013 - has called for New Zealand to show leadership in how to deal with the mess that was left behind.

PHIL JOHNSON/STUFF CIRCUIT Tohira who lost two children, five-year-old Laila and Hussain, 11, grieves at the cemetery, with one of her other children.

"When I was Prime Minister and visited Egypt, I was told of the toxic remnants of war from battles in which New Zealand was involved there in World War II – and which were still killing and disabling people.

"I took advice on what would be the most practical way New Zealand could help. It was decided that we would contribute by supporting mine victims."

In response, New Zealand provided financial support to help Egypt, which remains heavily land-mined 74 years after World War II ended.

"New Zealand as I recall was the first of the former combatants to step up and say it would provide support for dealing with that legacy, and this was very well received in Egypt," said Clark.

"New Zealand should build on this humanitarian legacy now in Afghanistan, including by cleaning up the toxic remnants of war discarded there."

A survey of the five ranges last year found that 39 square kilometres remained dangerous and needed cleaning up.