New laws, to be introduced in Parliament this week, have been welcomed by donor children and parents who have fought for more than a decade to remove what they say is a devastating veil of secrecy.
The Government promised donors would be protected from claims on their assets but said young people had the right to know and meet their parents. The move will bring NSW into line with other states.
The Assisted Reproductive Technology Bill will mean donor-conceived children, once they turn 18, will be guaranteed access to the donor's name, date of birth and education, as well as important medical information.
Health Minister Reba Meagher said the mandatory register would apply only to future donors. Individuals who donated anonymously in the past would not have to provide information for the register. They could choose voluntarily to provide details.
"The legislation will not oblige donors to have contact with their offspring and will not make them legally or financially responsible for those children," she said.
"In fact, the bill will offer additional protection for donors by providing that donated sperm and ova may only be used in a manner that complies with the donor's wishes. For example, a donor from a distinct ethnic community may stipulate that their donation is only to be offered to members of that community."
Premier Morris Iemma said he had seen the joy on both sides when donor fathers met their children.
"As a father of four, I know the importance of the bond of a family. This legislation provides hope."
About 37,000 Australians had been conceived with the help of donor sperm, said Sydney's Donor Conception Support Group. The group said current guidelines prohibiting anonymous donations did not go far enough.
Spokeswoman Leonie Hewitt, whose donor-conceived child has 29 half-siblings, said the possibility of a person inadvertently forming a sexual relationship with such a sibling was a major concern.
A register would enable donor-conceived people to access their medical history, and perhaps find their families.
But the issue of medical histories was overrated, said David Knight of Next Generation Fertility in Parramatta, a clinic that does not use sperm donated anonymously.
Dr Knight said most people did not have accurate knowledge of their family's medical history, even when they knew their relatives. Gene mapping would soon provide more answers than ever, he said, meaning knowing your family's medical history would be unimportant.
"People overemphasise the role of genes - a parent is the person who gives you care and love and cuddles you when you cut your knee," he said.
"There are emotional issues, generally cultural, and how we deal with those has not been sorted out."