A 36-year-old Wainuiomata man hacked his sleeping brother to death with an axe because he was annoyed he had not been thanked for cooking dinner, a court was told yesterday.

Fergus John Glen pleaded guilty in the High Court at Wellington to murdering his 33-year-old brother, Craig, on March 7 this year.

The mealtime slight was the final straw in a long-running feud between the men, court documents said.

Glen, single and unemployed, admitted striking his brother - who was married with three children - eight times across the face and neck with the axe.

Afterward, Glen returned the axe to the basement and, meeting his mother on the stairs, calmly told her: "I've done him ... [with] an axe."

The sound of the blows had jolted her awake.

She told police later she thought she had heard "woodchopping noises".

The victim's wounds included one that severed his spine.

The papers said Craig Glen was unlikely to have felt anything - the first blows would have knocked him unconscious or killed him.

Details of the brothers' feud leading up to the murder were withheld at the request of Glen's lawyers, Louise Sziranyi and Helen Croft.

The Crown prosecutor was Kate Feltham.

Justice Lowell Goddard remanded Glen in custody pending a probation report.

Glen is to be sentenced on November 21.