A Taranaki man who sent threatening letters to DOC over its use of 1080 poison has had his prison sentence cut in half on appeal.

Gregory Ross Buchanan was sentenced to five years in prison after pleading guilty to a representative charge of blackmailing, for letters including threats to take down helicopters supporting 1080 drops.

"Blood [will] fall. Watch this happen," one of the letters said. He wrote that it would be "a war like no other", and that New Zealand hunters had more guns than DOC and the police.

"We are going to bring you bastard (sic) to your knees," he said.


The 65-year-old wrote four letters to DOC between September 2017 and November 2018, threatening to release Sika deer into conservation land, including Egmont National Park, and to poison milk and meat processing plants.

Staff also received an envelope with what was suspected to be poison, but turned out on analysis to be blue chalk.

Police arrested Buchanan after an "extensive investigation" and charged him with blackmail.

The department's Taranaki office was shut down following the threats, and security guards had to be employed, costing $128,000 for the immediate response.

Buchanan went to the High Court at Wellington yesterday to appeal his five-year sentence, arguing that there were factual errors in the sentencing decision, that the starting point for sentencing wasn't in line with similar cases involving protest action, and that the judge didn't allow adequate discounts for his age and remorse.

The appeal judge did not consider the discounts were wrong, and would not accept fresh evidence on the alleged "factual errors", given Buchanan had pleaded guilty to the agreed summary of facts.

But the judge did find the starting point was too high, particularly given it was not alleged Buchanan had any involvement with releasing Sika deer.

The five-year sentence was replaced with two years and eight months in prison.