DISCOVERY: Officers exhumed a casket from Mangere Lawn Cemetery, in South Auckland, this week to find a doll inside.

A woman who faked a pregnancy prompted a police investigation when she feigned the baby's death.

Officers exhumed a casket from Mangere Lawn Cemetery, in South Auckland, this week to find a doll inside.

Detective Senior Sergeant Darrell Harpur said she confessed to staging the funeral to avoid telling her partner she was not pregnant.

Internal Affairs raised the alarm about six weeks ago after getting a request for birth and death certificates for a dead baby.

Mr Harpur said: "They came to us because there was no police record or doctor's certificate for it."

Police, who thought they might be dealing with the suspicious death of a child, went to see the 33-year-old woman, from Otahuhu, who claimed to be the baby's mother.

"We interviewed the alleged mum and she said there was no body in the grave."

Mr Harpur said the episode "revolved around" the woman's partner wanting a child. Initially the woman believed she was pregnant, then she learned she was not.

"But for some reason she couldn't tell him so she embarked on this subterfuge."

Police applied to exhume the baby's casket but had to wait several weeks before the Health Ministry gave permission.

"If we'd thought there was a baby in there we would have exhumed it a lot more quickly," Mr Harpur said.

"When we opened it, sure enough there was a doll wrapped in a blanket in the plot."

Mr Harpur said the woman was given a warning, which would be kept on file. "We've warned her for a deception-type charge in that the casket was buried in the koha area of the cemetery for people who can't afford a plot at the full price."

The casket is back in the ground because the cemetery administrator did not want to reuse the plot, he said.

"It was photographed and then covered up. The plaque's gone, though."

As far as police know, the woman has told only her partner the truth about the fake burial. Most family members still "think there is a baby there", Mr Harpur said.