The death of a 68-year-old woman in Auckland Hospital has sparked at least two investigations.

The family of Maureen Pineki are mystified about why she died.

Mrs Pineki, a great-grandmother from Mt Roskill, was seriously ill. She had type 2 diabetes and a painful skin condition, but her family did not realise she was near death.

"She shouldn't have been taken from us like that, because a couple of weeks ago she was well - apart from the cellulitis, she was struggling with that," her daughter, Marie Hanson-Alp, said yesterday. "She had a lovely, bubbly personality."

Mrs Pineki died in the hospital's intensive care unit last Saturday from severe brain damage.

Her blood sugar level had typically been high, but for several weeks before her death it had been low. She regularly checked herself with a finger-prick blood-sugar indicator.

People on diabetes therapy can be at risk of severe low blood sugar levels. Called hypoglycaemia, it can cause coma and irreversible brain damage, following initial symptoms like feeling unwell, shaking and anxiety.

Mrs Pineki had a home visit laboratory blood test on September 8, ordered by a diabetes nurse, Mrs Hanson-Alp said.

The next day, an ambulance was called when Mrs Pineki began experiencing symptoms of a low blood sugar level. Ambulance staff gave her glucose and her level rose.

But on September 10 the level apparently crashed again. Her husband, Tohomai Pineki, could not rouse her from sleep and at 2.30pm called an ambulance.

She was taken to hospital in a coma and did not recover.

The Auckland District Health Board's acting chief medical officer,Dr Margaret Wilsher, said that the board had reported Mrs Pineki's death to the coroner and was itself investigating.

"There are many potential contributing factors to this death and until we have fully investigated the sequence of events leading to admission and all the facts are ascertained, there will be no further comment."

The community pathology service, Labtests, also would not comment on the death until investigations were complete.

The St John ambulance service said it had begun an internal investigation and was participating in the health board investigation.

Coroner Peter Ryan said it was highly likely he would undertake an inquiry into the death.