A Kerikeri man will find out tomorrow if he will have to stand trial over a fire in a historic reserve triggered by a home-made bomb.

Ryan Moffat, 25, was charged with arson in the wake of the January 19 incident in which he buried the device and containers of petrol on a beach on Purerua Peninsula, in the northern Bay of Islands.

He then went up a hill with two friends to watch as he detonated the device using a firing box.

The resulting fire ignited vegetation on a nearby cliff and swept up the side of a historic pā at Rangihoua Heritage Park, the site of New Zealand's first European settlement.


About 30 firefighters with seven fire appliances responded to the blaze. A helicopter doused hotspots on the cliff the following morning.

In the Kaikohe District Court on Thursday Moffat's lawyer, Doug Blaikie, said his client accepted he would have to pay the $24,000 firefighting costs.

However, he was seeking a discharge on the charge of arson.

Blaikie argued his client did not believe he risked starting a fire, so he could not be criminally liable for arson even though events proved him wrong. If he thought it was a risk he would have buried the bomb 50m further down the beach.

Under cross-examination Moffat said he added the petrol to get a bigger bang and because it was cheaper than solid explosives, not because he wanted to start a fire.

Prosecutor Duncan Coleman, however, said 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.

Judge Russell Collins has reserved his decision, which he is due to deliver on Friday.

The pā is not thought to have been damaged beyond the short-term loss of vegetation and no burnt kiwi or kiwi nests were found, despite the area's high density of the flightless birds.