Over half of these families are looking after their grandchildren due to drug abuse.
Minaora first noticed something was wrong with her daughter and her two grandchildren in 2011. Their house was a mess, her daughter wouldn't get out of bed and there was no food in the fridge.
"And I saw something odd. The children had a bedroom each but they had dragged one of the children's mattresses into the other room so they could be together. It struck me something wasn't right."
But it wasn't until a year later and she saw her daughter's face twitch that it clicked.
"I immediately said to her 'daughter are you on P?' and she said 'yes' I said 'and how long for?' and she said 'maybe two years, three years'.
"It felt as though a horse had kicked me in my chest."
Minaora looked after her daughter's two, then three, children on and off for four years. She has recently taken on the legal guardianship of her son's 1-year-old daughter as he is struggling with his own meth addiction.
She described that time as an incredible stress. Minaora was juggling her full-time job with a daily two-hour commute, raising her grandchildren and supporting her children through their addiction. Her partner has had to quit her job to take care of the latest grandchild.
Minaora said methamphetamine took over her daughter, rendering her incapable of parenting. She would go through periods of not using meth, but the tell-tale signs of a messy house and neglected children would resurface.
"This was very heartbreaking for our family. We had to see our girl being taken hostage by a chemical that altered her personality so much she was not recognisable to us.
"I felt like her wairua, which is a spiritual aspect that is very important for us as Maori, wasn't in her body. I felt as though there was this imposter. I called her a zombie."
The children came to Minaora with meth-contaminated clothes and behavioural issues. The boy, now 10, was diagnosed with ADHD and suffers from a severe anxiety disorder. They have both received counselling.
Minaora, now in her mid-50s, used to call up the drug and alcohol hotline to speak to the specialised meth team for advice. Then she discovered Grandparents Raising Grandchildren. She said she would phone founding trustee Diane Vivian and vent about her situation.
"She could validate everything I was saying and she knew the character of my daughter. Because when I was speaking about my daughter I was speaking about thousands of other people's daughters.
"Grandparents Raising Grandchildren are a light in the darkness."
35 support groups nationwide
Nationwide 3700 families, 6400 caregivers and 12,000 children are members of Grandparents Raising Grandchildren.
Chief executive Kate Bundle said drug abuse is the number one reason grandparents raise their grandchildren. A survey last year found in 53 per cent of families drugs were a major factor. Methamphetamine was the only drug that seemed to cause a family breakdown, Bundle found.
"In a lot of cases the children are exposed to P use. Either the manufacture of P or parents smoking around them.
"A lot of these kids are sick. Their clothing, bedding and toys are so contaminated it has to be destroyed and they have nothing.
"It is heartbreaking. I wish people would realise how devastating this drug is."
Bundle said their membership is increasing 20 per cent a year. They have 35 support groups around the country that will be holding fundraisers for awareness week.
"Suddenly people realised there is some support and started to link together. It has grown like a mushroom."
The top three reasons children end up with their grandparents are drug addiction, domestic violence and family breakdown. Bundle explained that these three often come as a package.
She said they often leave the child traumatised and 40 per cent of these children are diagnosed with a disorder such as ADHD, foetal alcohol syndrome or autism.
Money and respite are the two key challenges grandparents face as caregivers, Bundle said. Often a grandparent has to give up work to care for the child and they have to live off a benefit. They also find it difficult to find a caregiver who can give them a break.
Despite all of the hardships these grandparents would go to the ends of the earth for their grandchildren, Bundle said.
"There's nothing quite like seeing the world through a child's eye. For a lot of the grandparents that's what keeps them going. The funny things they say, and the love they give to them.
"That unconditional love is so strong."
*Minaora is a pseudonym as she wants to protect her children's identities.
Top 12 reasons grandparents raise grandchildren
• Drug addiction
• Domestic violence
• Family breakdown
• Neglect
• Parent unable to cope
• Alcohol abuse
• Mental illness
• Child abuse
• Very young parent
• Abandonment
• Imprisonment of a parent
• Death of a parent
