Children of prison inmates have been found to have a range of physical and mental health problems.
Some 8500 people are currently held in New Zealand prisons. Researchers estimate they have about 20,000 children and the number is growing.
Dr Liz Gordon, who is leading a three year study, says these children often have anxiety, anger and other emotional problems, as well as general poor health.
She says the children of prisoners are seven times more likely to end up in prison themselves.
Researchers hope to find ways to break the cycle in the next two years of their work.
The study, entitled Invisible Children, is being run in collaboration with the community group Pillars, which supports children with parents in prison.