The territory's Domestic Violence Crisis Service estimated there were 77 deaths between 1988 and April 2012 that were either directly or indirectly caused by domestic violence in the ACT.

Of those, 64 women, 11 men and two children died as a result of murder, suicide, overdose, or a cause not known to the organisation.

Those deaths had left 134 children motherless. The vast majority of those children were under 18.

Executive director Mirjana Wilson said the impacts on those children varied and depended on factors including whether their mother was murdered or died by suicide and whether they witnessed it or not.

"There's no kind of one response but we do know there's significant trauma for those children and there is a trauma that will be there for the rest of their lives."

More than 100 people gathered in Canberra on Wednesday night at a candle-lit vigil to remember the victims of family and domestic violence, part of a nation-wide event.

Domestic Violence Prevention Council member Dr Sue Packer, a paedeatrician, said children who lost a parent due to domestic violence had often witnessed "scary" relationships and seen their mother hurt or distressed.

"Children also tend to blame themselves for violence and think if only they had been better behaved, and you can just imagine how that escalates if their mother dies.

"There's this overwhelming sense of grief and guilt and sometimes that bubbles up unto anger."

An infant whose mother died often had to be rapidly weaned and they were often distressed by the sudden change in the sights, smells and sounds.

"It's quite shattering and it's very distressing for people dealing with it," Dr Packer said.

"People often think babies are sheltered from it but quite a bit might remain in their pre-verbal memory and it's certainly something that has a huge impact."

Dr Packer said older children often had trouble coming to grips with the permanency of their mother's death and the realisation their life would never be the same.

"You can get the full range of responses, from really angry, acting out, destructive behaviour. They're often the ones who get the attention.

"The ones we pay less attention to are the quiet, withdrawn children who look like they're coping but they're often quite despairing.

"It's among that group that you often get self-harm or suicide."

Dr Packer said the grief was made more complex if their surviving parent was the alleged perpetrator.

"It's often the grief of losing two parents because the other parent might be incarcerated, or suicide, or have to be treated for mental health problems.

"It's an ongoing nightmare and there's no avoiding the fact it's going to become those children for the rest of their life."

Three women and one man have died due to alleged family violence in the ACT so far this year.

Young mothers and alleged murder victims Tara Costigan and Sabah Al-Mdwali each left three children, including two infants, behind.

The Domestic Violence Crisis Service said their figures on fatalities were not official ACT statistics, but had been taken from their client files and documented deaths they were made aware of in that period.

Experts cannot say exactly how many deaths have been linked to domestic violence in the territory, given some were due to homicide and other causes.

The ACT government announced the Domestic Violence Prevention Council would conduct a review into domestic and family violence deaths in July last year.

The review's findings are expected to lead to reforms that could reduce the number of deaths, including through sharing information by courts, law enforcement and social service agencies.

Support is available for anyone who may be distressed by phoning Lifeline on 131 114.