The number of investigations opened by police relating to child safety has continued to rise in the last four years.

The figures released under the Official Information Act show that last year alone, 12,437 cases were opened by police.

On average, that is 34 cases opened per day relating to concerns of criminal behaviour against a child.

In 2014, 10,554 cases were opened - with the number increasing annually since then.

It is unknown how many of those cases were substantiated, resulted in charges being laid or had further involvement from Oranga Tamariki.

Detective Senior Sergeant James Patea told Stuff police investigated all reports of criminal offending against children.

Continued messaging about what warning signs to look for was helping bring better awareness in communities, and may have contributed to the continued rise in cases, says James.

"If the public are concerned about the welfare of a child we should be contacted immediately. If children are being harmed we take it very seriously.

"We encourage people to report any well-founded suspicion. Even if their suspicions are wrong."

Reports of serious concerns of physical abuse, sexual abuse or neglect are investigated by specialist child-protection teams.

Child-protection cases that do not meet the threshold for serious abuse are still investigated by police staff outside the child-protection teams.

Counties Manukau remained the district with the most cases opened a year. As opposed to Wellington District which has seen a decrease in cases opened since 2014.

Oranga Tamariki's general manager of practice, Nicolette Dixon, agrees that people who had concerns should contact Oranga Tamariki or police.

"Our contact centre is staffed by social workers. People can ring and seek advice before they take a course of action.

"... We might bring families together to talk about those worries are. We might simply be giving people advice - every situation is a little bit unique."

Nicolette believes the rise in cases was, in part, due to concerns around methamphetamine and synthetic drug use.

Child Matters chief executive Jane Searle says while it's important not to look at the statistics in isolation, it showes the high rate of complaints police were dealing with.

"It is an indicator of how serious the issue is overall and the workload of police, Oranga Tamariki and other community organisations."

While communities had become better at discussing the issue of child abuse, the amount of children harmed was too high, says Jane.

"There is a lot of good discussions at the moment. That is very different from action."

THIS YEAR

• A 22-year-old man was charged with the murder of four-week-old baby Maree Takuira Mita Ngahere after she was found dead in February and an autopsy revealed she had died of non-accidental injuries.

• A 39-year-old man accused of murdering 17-month-old Sadie-Leigh Gardner in March this year has pleaded not guilty to her murder after she was taken to hospital with serious head injuries.

• In July a 30-year-old man was charged with the murder of a 10-month-old boy on the West Coast after the boy suffered a serious head injury and later died in hospital.

• In September Aaron Archer was found guilty of the murder of 2-year-old Ariah Dawn Roberts, who died as a result of head injuries.

-Stuff/Tommy Livingston.