A Darwin man has been jailed for life for burning his neighbour to death.

Darin Andrew Clare, 37, was sentenced to life imprisonment, with a non-parole period of 20 years, after pleading guilty to murder.

The Northern Territory Supreme Court was told Clare poured petrol over neighbour Philip John Cure, 60, because he believed Mr Cure had been harassing Clare's sister and her family.

It heard that the attack at a Darwin rural area property came after noise from Mr Cure had interfered with Clare's television viewing.

Justice Peter Barr said that when Clare lit up the petrol, his neighbour was engulfed in a fireball.

He said the attack was cruel and callous.

When other neighbours went to Mr Cure's aid, the judge said, the victim's whole body was on fire; he was literally a human torch.

Mr Cure, who was also known by the nickname 'Pig', later died from burns to 90 per cent of his body.

The judge said it was "deeply disturbing conduct that came out of the blue".