(CNN) New Zealand's government watchdog will investigate the practice of authorities seizing newborn babies from their mothers -- including some when they are still in hospital.

Taking infants into state care -- known as "uplifting" -- has been making headlines in the country since last week when an investigation by local media outlet Newsroom showed authorities attempting to take a seven-day-old baby from its 19-year-old mother -- who was of Maori heritage -- while she was still in the maternity ward in Hawke's Bay Hospital, on New Zealand's east coast.

On Wednesday, New Zealand's Chief Ombudsman Peter Boshier announced a wide-ranging, independent investigation intothe Ministry for Children's uplifting process, making it the third inquiry to be announced since the story hit headlines.

Last year, judges ordered 281 babies to be taken into care and 71% were of Maori or Pacific Island heritage, the government said in a statement.

In New Zealand's most recent census in 2013, 14.9% of the then population of 4.2 million people identified as Maori, while 7.4% identified as of Pacific Island heritage.

Some have raised concerns that Maori and Pacific Island babies are disproportionately affected by "uplifts" due to institutional racism . Over 15,000 people have signed an open letter online urging the government to " stop stealing Maori children ."

"No one is more vulnerable than a newborn baby," Boshier said. "I think the public needs assurance that the right policies and processes are in place for their protection while at the same time safeguarding the rights of (family)."

High rates of child abuse

New Zealand has one of the worst rates of child abuse in the developed world. According to Unicef , the children's ministry receives over 150,000 reports of concern relating to the country's 1.1 million children each year.

-- after The country has been trying to tackle its high child abuse rates. In 2017, the government created Oranga Tamariki -- or the Ministry of Childrenafter finding that the system under the former ministry, was "ineffective" and had poor long-term outcomes for children in care.

newly-formed Oranga Tamariki has also come under fire. In March, it However, thenewly-formed Oranga Tamariki has also come under fire. In March, it announced that in the second half of 2018, there were over 300 instances of neglect, emotional, sexual or physical abuse of children in its care.

Prime Minister Jacinda Ardern speaks to media on May 30, 2019 in Wellington, New Zealand.

In a statement to CNN Wednesday, Oranga Tamariki's chief social worker Grant Bennett said the decision to remove children from their mothers was a "last resort action" which required a judge to make a custody order. Under New Zealand law , a parent who has already had a child removed from their care must have a mandatory assessment of whether they are likely to harm their second child.

"The physical and emotional state of children taken into our care would often shock and sadden most New Zealanders," he said, adding that some children were exposed to family violence, drugs being sold from the home they lived in, parental drug and alcohol abuse, sexual and physical abuse and chronic neglect.

"Every situation we deal with is complex, but it only takes a moment to harm a baby," he said. "Ultimately we all want the same thing, for all babies to be in the safe, stable and loving care of their parents and (family)."

Oranga Tamariki is conducting an internal investigation into the Hawke's Bay case. The Children's Commissioner -- who has oversight over Oranga Tamariki -- is also reviewing the ministry's policies around the care and protection of Maori newborns.

In a statement , Children's Commissioner Judge Andrew Becroft said that the mother-child relationship was denied to too many Maori children.

"It's been increasingly clear over recent days and weeks that the community as a whole is profoundly uneasy with the way our current care and protection of (Maori children) is carried out," he said.

Prime Minister Jacinda Ardern -- who last year announced a royal commission of inquiry into children abused in state care -- told TVNZ Tuesday that New Zealand had two problems: too many children in state care and high rates of child abuse.

But she stood by Oranga Tamariki, saying it was on the right track.