The body of Leanne Kingston, 39, was found by her sister inside her home at Cargill St, Papakura, about 4pm.
Detective Inspector Mark Gutry said police were keeping an open mind about the circumstances surrounding her death.
However, initial investigations showed there "were obvious signs of violence within the property".
Mr Gutry said there was a disturbance at the house about 12.45pm and a neighbour reported hearing what sounded like a window breaking.
He said the scene examination was likely to go into tomorrow and urged anyone with information that might help the inquiry to contact police.
Ms Kingston, a triplet, lived at the house with her children, who are aged eight to 19, and with whom she shared custody with her ex-partner.
The children are being cared for by relatives.
On Monday, Ms Kingston's family became concerned when she failed to collect one of her children from school.
Residents said there had been several break-ins in the area.
One woman, who had been a victim of a home invasion and didn't want to be named, expressed concern for the safety of solo mothers in the street.
Meanwhile, friend and neighbour Margaret Tate said Ms Kingston and her on-and-off partner couldn't live together but could not stay apart.
"They used to have time out, he would go out of the country or to the South Island for a while," she told the New Zealand Herald.
Ms Tate said Ms Kingston was found in the bathroom, which she had been cleaning, and there was a smashed window nearby.
