A man has pleaded guilty to stabbing his flatmate in the back during an argument, leaving her needing surgery to remove the blade.

The knife came close to damaging the victim's spinal cord and lung and left a 10cm deep wound.

John Franklin Dean, 68, pleaded guilty this afternoon to wounding with intent to injure, after originally being charged with a more serious count of wounding with intent to cause grievous bodily harm.

He appeared in the Wellington District Court to make the plea.

Advertisement

According to the summary of fact, Dean was arguing with the victim on July 13 last year when he threw a punch at the 52-year-old woman's face.

As a result he was asked to leave the flat, at which point he retreated to his bedroom, grabbed a knife, returned and plunged the blade into the woman's left shoulder while she had her back turned.

He used enough force that the knife became lodged in her shoulder and required surgery to remove.

An examination revealed the knife came close to a significant blood vessel, as well as the lung and spinal cord.

Dean, who had been in jail since the attack was released on bail earlier this month.

He will be sentenced in Wellington on February 26.

Judge Bruce Davidson convicted him and gave him a strike warning under the Three Strikes legislation.