The Government says it has strengthened safeguards surrounding a collection of blood samples from more than 2 million New Zealanders.
It has also been revealed that heelprick samples, also known as Guthrie cards, have been used to identify Christchurch earthquake victims.
The samples have been collected since 1969 from newborns as part of screening to detect serious disorders such as cystic fibrosis.
Concerns over privacy and access have been addressed in stronger protections for the collection, announced by the Government on Friday.
Individual written consent will be needed from parents or children for research on samples collected before June this year.
Samples collected since June may be used for research if parents consent to the cards' storage and if the research has ethical approval.
Police have confirmed they used heelprick tests to help identify victims of the February quake.
The National Testing Centre, which does the screening, says it released five cards for quake victim identification and is in discussions about releasing more for victims of the explosions at Pike River mine in November last year.
Call for even stronger protection
Researchers have welcomed the decision to retain the Guthrie cards indefinitely, but the Privacy Commissioner says even stronger protections are necessary.
Marie Shroff supports the changes made, as well as the reasons for gathering the samples, but is calling for legislation that would ensure the public is consulted over any changes in future.
"We want to make sure that the information that is held about people on these cards is controlled in some statutory way that allows for good public consultation and a good transparent process if those cards are to be used for anything other than their primary process - which is to protect the newborn."
Associate professor Andrew Shelling, of Auckland University, says he has used Guthrie cards supplied by families to extract DNA and conduct genetic tests to identify why children have died, which is sometimes due to an inherited problem. He says the cards are invaluable.