A man who intended to poke his girlfriend in the back with a knife to get her to cook him dinner faster ended up killing her, the Northern Territory Supreme Court has heard.

Andrew Norman, 31, from Yuendumu, had been drinking for three days with Rosebud Munungurr, from Yirrkala, when the pair went to a Darwin home in August last year.

Norman had cut up some meat and wanted Ms Munungurr to make damper.

When she delayed, he said to himself, "I'll stab her a little bit, one time."

Norman's lawyer said he intended to poke Ms Munungurr, but instead plunged the knife 10 centimetres into her back, severing an artery.

Norman said he was very drunk and wobbly on his feet, which he thinks contributed to the force he used.

His lawyer said Norman was shocked and confused when the woman fell to the ground.

He carried her outside, tried to perform CPR, called for an ambulance and when police arrived, told them he had stabbed her.

Ms Munungurr's sister told the court she has lost three of her sisters to alcohol-related violence in Darwin's long grass and she fears for the safety of another.

Robyn Munungurr said she often came to Darwin to take her sister home to stop her drinking and to go hunting in the bush.

"I've lost three sisters now to drink and violence," she said.

"I have two left."

She said she cries every day for the sisters she has lost.

Norman has pleaded guilty to reckless manslaughter and will be sentenced next week.