The people who caused a blaze that ripped through a scrubby hillside in Wanaka for two days could be prosecuted under new legislation.
It took more than 40 firefighters and eight helicopters with monsoon buckets to battle the blaze on 3 January.
Fire and Emergency's regional manager rural Mike Grant said the overall cost of the operation was estimated to be between $550,000 to $600,000.
Under the new legislation, Fire and Emergency could try to recover the cost of the operation from the person responsible for the fire through formal legal action.
He added that it has not yet been decided whether the owners will face prosecution, or whether costs will be pursued.
Mr Grant said the property owners had removed the embers from an outdoor fire, and placed them in a tin can.
"They'd left them for two days and then they discarded them in a location where they have been doing for the last 10 years," he said.
The owners thought the embers were dead, but about two days later they saw smoke and flames coming from where they had put the embers.
"They did some follow up work to contain and extinguish that, it was just on their property and then left the sprinkler on it. It was several days after that the fire started from that location," Mr Grant said.
He added that the fire did not need a permit even though there was a fire ban in place because it was in a fully enclosed fireplace.
"[The property owners] had done everything that they thought was the right thing to do and have just come up a bit short and been a little bit unlucky.
"They have been very helpful from the reporting of the fire, to the ongoing support of the fire suppression operation all the way through.
"We have been in regular contact with them and we will maintain that contact over the next little while till we resolve the issue."
The site of the fire is still being monitored for hot spots, especially during the hottest parts of the day, but none have been found in the past two days.
Fire and Emergency principal rural fire officer Graeme Still said that anyone discarding embers should put them in a bucket, and douse them with water, stirring them occasionally and letting them soak for several days.
"Every year we get several calls to fires that start from ashes, so it's a good reminder to doubly, even triply, check them," he said.
"Even best practice can catch you out when the fire danger is as heightened as it is now.
"There's absolutely no moisture in the ground and things can escalate pretty quickly."