And a third family claims they had approached Norwood Park several times in the 1990s and 2010s, seeking details on the exact location of the ashes of a family member.

They say they are yet to receive an answer from Norwood Park.

The revelations follow a story in The Canberra Times last week about Eddy Mol, who discovered in 2016 the ashes of his premature baby boy, Timothy, who died in 1978, were missing.

Mr Mol wanted to honour his late ex-wifes dying wish that her ashes be mixed with her sons and scattered together on Mount Kosciuszko.

But when he contacted the Norwood Park crematorium to retrieve them, he was told the ashes had gone missing.

Mr Mol said the revelation came as a shock, as he and his ex-wife, Ruth Freeman, had been visiting the cemetery and laying a flower by their sons plaque every year since he died in 1978.

That's the hardest part, going there every year for his birthday and then now knowing that he was never there in the first place, he said.

He was glad his ex-wife, who was a quadriplegic following an accident in her 20s, died not knowing the truth.

It's hard to lose your son once, but it's harder to lose him twice, he said.

The crematorium broke the news to him after they failed to locate the tube containing Timothys ashes in the Childrens Court garden, where they were supposed to have been buried in the ground beneath a plaque.

Mr Mol eventually told Ms Cheyne, who brought up the issue in an annual reports hearing before the Legislative Assembly last week.

Norwood Parks general manager Stephen Beer confirmed a comprehensive search had been carried out on all the likely areas of the memorial gardens.

He also said he and his staff would keep looking for the ashes.

We're very concerned about it, we hate this sort of stuff when it happens, he told Fairfax Media.

This is the first time that it has happened since I've been here. I've been [here] in different capacities for about 11 years.

He maintained he was absolutely confident that no other families would find themselves in the same position as Mr Mol.

However, Ms Cheynes office has revealed that two other people, who did not want to be named, had since come forward claiming the crematorium, which services all the ACT, had not been able to locate the ashes of their loved ones.

All three cases involve the ashes of babies who died in the late 1970s, and whose remains were interred in the Children's Niche Wall, and later moved, with the families' permission, to the Children's Court Wall in 1992.

A spokeswoman for the privately run crematorium told Fairfax Media on Monday that other than the case of Mr Mol, she was unaware of any similar cases during the last 11 years, since Mr Beer has been working there.

But Ms Cheyne said she was hearing a different story.

"Not only do these families deserve answers and deserve closure, but Norwood needs to provide broader assurance to the community about their processes," she said.

"I am particularly concerned that Norwood has said they are not aware of other approaches from families in the past 10 years when the contact Ive received strongly suggests otherwise.

Losing a child is one of the most distressing things that can occur in someones life. Each of these families had trusted Norwood with the care of their loved ones ashes. To now not know where these childrens ashes are just compounds that distress."

In the meantime, the City Services directorate, which is the regulator for cemeteries in the ACT, was first made aware of the incident in the annual report hearings last week, and is now investigating.