A sperm donor father who only met his adult daughter six weeks before she died of bowel cancer has backed Victorian moves to strip donors of anonymity.

Under a bill introduced into the Victorian Parliament, the name and birthdate of donors will be released to biological children, regardless of donor consent.

If the name of the donor was not recorded, the government can now order any donor it suspects could be the father to undergo a DNA test.

Since the late 1980s, all states have moved to warn new donors their offspring will have the right to know their identity.

But until now, no state in Australia has retrospectively cancelled the guarantee of anonymity that donors were given in the early days of IVF.

For the tens of thousands of people who were conceived using donor sperm, and who want to know the identity of their biological fathers, it is a welcome development.

But it has left some donors who may have fathered dozens of children feeling anxious and exposed.

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Contacted by dying daughter with just six weeks to live

Ray Tonna, who donated sperm donation in the 1980s, is not one of them.

In 2013 Mr Tonna received a letter telling him a woman called Narelle Grech wanted to get in touch.

"A few days later, she phoned me and just hearing the voice was a revelation," Mr Tonna recalled.

"I just wanted to tell her everything about me, and she wanted to know everything about me.

"It was just beautiful. From the moment she got out of the car I knew straight away she was my daughter.

"I love her, you know, that's all there is to it."

But Mr Tonna's time with his newfound daughter was short.

Ms Grech had advanced bowel cancer and died six weeks later.

Ms Grech lobbied for much of her adult life to find her biological father, but because she was conceived in Victoria before 1998 she had no legal right to know his identity.

In 2013 then-Victorian premier Ted Baillieu intervened and demanded the relevant department contact Ms Grech's donor.

Her story helped spur dramatic changes in Victorian law, part of which was introduced to Parliament this week.

Mr Tonna supports the moves.

"Try and understand that these people have a right to know their biological heritage," he said.

"It's really truly and long overdue."

IVF pioneer says new law goes too far

One of Australia's IVF's pioneers, Gab Kovacs, believes the new law is extreme.

Professor Kovacs and other doctors convinced hundreds of Victorian men to donate on the basis they would be anonymous.

"I feel very sympathetic to the offspring, but they weren't made a promise and in fact all their parents signed a consent form which clearly said the donation would be anonymous forever," he told 7.30.

"To suddenly go back on a promise makes me feel bad, because I believe a promise is a promise is a promise."

Kimberley Turner is trying to track down her donor after having children of her own ( ABC )

Ian Morrison was a regular sperm donor in the 1970s and could have fathered up to 30 children.

He said agreeing to anonymity was a prerequisite.

"They would not accept the donations unless I was prepared to remain anonymous, and by anonymity they meant that I made no attempt to contact the receiving families," Mr Morrison said.

"I am annoyed that what I agreed to all those years ago is suddenly being thrown straight out the window."

Kimberley Turner found out she was donor-conceived 10 years ago and, now a mother herself, she wants to learn more about her genetic background.

"I think it is really important, for everybody to have the same opportunity to discover who their family ties are, how they link to the rest of the world," she said.

"I'd just like to look at his face, and see a reflection of myself in it."

Donors allowed to contact children

But the search for a person's biological family works both ways and as part of the changes, sperm donors, too, are being given more rights.

Although they cannot get their offspring's names without consent, they can contact them through a central registry.

This creates a new problem, because estimates are that half of donor-conceived children do not know they are donor-conceived, and already some have received letters alerting them to the fact their fathers are not who they think they are.

Since Ms Grech tracked him down, Mr Tonna has learned he fathered eight other offspring through sperm donations.

And Ms Grech's death from bowel cancer has raised the spectre that he may have passed on a genetic predisposition to the disease.

"As a responsible parent, someone who's been responsible for bringing these people into the world it's my duty to make them aware of a medical condition that they should have tests for," Mr Tonna said.

He plans to use Victoria's new law to get in touch with his offspring despite the fact they may not know they are the product of donor sperm.

"People have a right to know who they are, where they came from," he said.

"It's part of our story. We all have a narrative."