The two men were struck in the wrist and leg by shrapnel.
The soldiers - a corporal medic and a lance corporal - were described as "walking wounded" and taken to Bagram Airbase hospital, 180km east of the Kiwi province.
One soldier returned to New Zealand three days later and the other was able to continue with the Crib 21 deployment, the final rotation of 10 years of Kiwi presence in the area.
The soldier was charged under the Armed Forces Discipline Act, and was fined and banned from taking part in subsequent firing exercises.
Ten New Zealand soldiers were killed in Afghanistan during the 10-year deployment, which ended in April last year.
Herald on Sunday inquiries were sparked by a former Defence Force corporal's claims he had been ordered to illegally modify Claymore mines so they were tripwire-activated.
Doing so would be in breach of international anti-landmine treaties.
He said the order, given by a senior commander, was never carried out.
Chief of Defence Lieutenant General Tim Keating said Kiwi forces had not tried to modify Claymores, and had always used them in accordance with international law.