A Hamilton man has been fined and sentenced to community work for performing a home castration on a dog, that went horribly wrong.

The pet had scrotal wounds when the man took it to a Hamilton vet in August - he said it had injured itself while jumping over a fence.

The vets who examined the dog found it had actually been deliberately castrated.

The SPCA's Ric Odom says the case should deter others from attempting to castrate their dogs at home.

The man was sentenced to 150 hours of community work, fined $350 and banned from owning animals for five years.