A New Zealand Defence Force Court of Inquiry said it had completed its inquiry into the fire.
It found the range practice was conducted in accordance with existing fire permit procedures and the range standing orders.
A fireman and fire appliance were present and this was over and above the requirements of range standing orders.
The court of inquiry said procedures are already underway at West Melton to address findings to minimise any future fire risk.
These included; enlargement of effective fire breaks along the range boundary and inside the range, enlargement of the cleared gravel area around the grenade range to remove the fire risk from hot fragments, the assessment of already cleared impact areas on other ranges at West Melton to reduce fire risk, and revision of the range management plan with defence contractors to ensure ongoing maintenance is sufficient to minimise fire risk and that contractual standards are maintained.
"Defence will be taking every measure and safety precaution at West Melton range to ensure that an incident such as the fire on January 23 does not occur in future."
Once implemented the defence fire breaks surrounding West Melton range will benefit neighbouring properties as the range will effectively become a fire containment zone.
Compensation to organisations and some residents may be required but this assessment is being settled between insurance agencies as it's outside the court of inquiry's scope.
A pine plantation fire off Thompsons Rd, West Melton, destroyed 80ha on January 11 and 300 motorcyclists were evacuated from Moore Park Speedway along with local leaseholders and sheep stock downwind of the fire.
A scrub fire which started on private land behind a quarry in Broadfield on January 10, destroyed two homes and affected about 30 properties over 150ha near Selwyn, Shands and Robinsons Rd.
It was estimated the blaze cost $200,000 to fight.
Selwyn District Council Principal Rural Fire Officer Wilson Brown wouldn't comment over whether the army would face the cost.
