About 30 firefighters with seven appliances responded to the blaze, a helicopter finishing the job the next morning.
Moffat had told the court that he had not believed he was risking starting a fire, so he could not be criminally liable for arson. If he had thought there was a risk he would have buried the bomb 50 metres further down the beach.
He had added the petrol to get a bigger bang, and because it was cheaper than solid explosives, not because he wanted to start a fire.
Police argued that Moffat's friends had alerted him to the bomb's proximity to cliffside vegetation, and to get to the beach he had driven or walked past at least half a dozen "No Fire" signs.
Police appealed the District Court's decision to discharge him without conviction on the grounds that the sentencing judge erred in his assessment of the gravity of the offending by overlooking relevant considerations.
They claimed that the judge had overlooked that Moffat was put on notice by his associates that the hole he had dug and into which he put the explosive device was too close to vegetation, that there was a total fire ban in place at the relevant time, and that he was familiar with and held pyrotechnic certification and experience.
Further, the sentencing judge erred in his assessment of the consequences of a conviction on Moffat's job, his family business, ability to travel and obtain mortgages, which were not supported by available evidence.
"Mr Moffat's actions were more than naïve as the judge suggested. They were also much more than 'a stupid thing to do', again as the judge suggested," Justice Edwin Wylie noted in his judgment.
The area around Marsden Cross is known for its large North Island brown kiwi population, a witness to the fire reporting that kiwi were heard "screaming" as flames swept up the hillside, but an inspection by DoC rangers found no dead birds or fire-damaged nests. A dead kiwi was subsequently found, but DoC doubted that it had succumbed to the fire.
