UPDATED 4.38pm: A hunter who accidentally shot and killed his son has been granted a discharge without conviction.

61-year-old Stephen Long has been sentenced in Invercargill District Court after early pleading guilty to the careless use of a firearm causing the death of his 24 year old son Samuel.

The shooting occurred in March this year on Stewart Island.

Lawyer John Lewis says Mr Long believed he was shooting a deer.

"He made a dreadful mistake, yes that's true, but in the end his level of culpability was very low and the consequences to him have been absolutely overwhelming."