One of the girls had to express breast milk into a sink after being separated from her baby. They were not given toilet paper and were refused contact with their families and lawyers while in custody, they told the newspaper.
In releasing the report today, IPCA chair Judge Sir David Carruthers said the importance of treating young people in a fair and humane manner should not be underestimated.
"Detaining young people in police cells is unfortunately sometimes necessary but it can miss the opportunity for a more constructive response to a young person's offending.
"We need to focus on preventing and reducing youth offending as well as identifying alternatives to police detention."
He said improvements could and should be made, and he hoped the review would help reduce the number of young people held in cells.
Children's Commissioner Dr Russell Wills said when young people were arrested for their own safety or the safety of others, it was an opportunity for them to turn their life around.
The report noted that some interventions, for instance supported bail, could reduce offending.
"If on the first meeting they are treated respectfully and they're clear about what's happening then they're much more likely to make the right kind of choices.
"These are young people who are in crisis because of the choices they're making. They are going to grow up, so how we respond to them at this point can have a very important impact on the kind of adult they become. It's important not just for them but for society as well.''
Chief Human Rights Commissioner David Rutherford said detaining young people in custody should always be a last resort.
"None of us want to see children in police cells. It's as simple as that, and this report recommends ways to stop what is at heart an issue of human rights.''
By the numbers:
* Last year 213 young people were detained in cells for an average of 1.9 days.
* Overall rates of youth apprehensions declined between 1995 and 2008.
* Significantly more young males are apprehended than females; but while the rate of young males being apprehended is decreasing, the rate of young females is not.
* Apprehension of Maori young people is almost three times the rate of Pacific or New Zealand European youth and apprehension of Maori children is almost five times the rate of pacific or New Zealand European children.
* NZ has four secure youth justice residences and a total of 146 beds.
Practices in NZ police cells inconsistent with accepted human rights standards include:
* having cell lights on 24 hours a day (to allow suicide monitoring);
* it being difficult for family to visit;
* a lack of ventilation and natural light;
* cells being unclean;
* a lack of showering facilities/privacy;
* inadequacy of food; and
* lack of access to exercise, recreation and education.
Young people reported:
* being treated as an adult, not as a young person;
* being treated unfairly;
* the use of force;
* feeling discriminated against; and
* not having their medical and/or mental health needs met.
