The woman, who was almost 90 years old, was taken to hospital. The man, who was her son and her carer, was taken into custody.

"This is a classic case of elder abuse," said Senior Sergeant Alasdair Gall, of Victoria Police's family violence command.

"You've got a controlling son who, once the dad's out of the scene, started targeting his mother and she's not in a position to defend herself."

As Australia's population ages and with an estimated half a million people predicted to be stricken with dementia by 2025, police and social workers warn that abuse of the elderly is a growing problem and fast-emerging as the little discussed new front of domestic violence.

"It's going to affect someone you know," Senior Sergeant Gall said.

"It really is abhorrent - you would think older people could trust their family, but unfortunately they can't in all cases."

Experts will meet in Melbourne on Thursday to discuss elder abuse, which spans neglect as well as financial, emotional, physical and sexual abuse of the over-65s.

Australian-first research shows 38 per cent of perpetrators are the sons of victims, and many of the abusers are themselves struggling with substance abuse and mental health problems.

The Australian Law Reform Commission will release its 15-month inquiry into the issue, calling for the federal government to work with states and territories to develop a national plan to combat the problem.

It says a nuanced approach is needed to balance the autonomy of older people while also protecting and responding to those who are at risk.

Among a suite of recommendations is a national employment screen for aged care workers and a new reporting structure requiring providers to flag suspicions of abuse, neglect and cruel treatment to an independent agency.

It also recommends a new model for preparing and executing wills, that banks take on greater responsibility to prevent financial abuse, and national guidelines governing how tribunals support elderly people who are subject to guardianship applications.

Calls for a national framework are being echoed by Victoria's Public Advocate, which also wants research to quantify abuse rates among older people, including vulnerable groups such as those with disabilities.

Public Advocate Colleen Pearce said elder abuse, violence and neglect was a pressing social policy issue.

"All elderly people can be vulnerable to abuse, neglect and exploitation but there is clearly a new cohort of people with cognitive impairments who are at risk," she said.

"People need to be aware and alert to it, whether it's their family or neighbours, and they need to take action."

Data from the Public Advocate shows there was "clear evidence" of abuse in 13 per cent of its guardianship cases involving the elderly.

But this is likely to be a massive under-representation of the scale of the problem, as the Public Advocate is only ever appointed guardian when VCAT orders that no one else is able to meet those responsibilities.

Recent cases of elder abuse in Victoria include:

• A woman with dementia who was financially exploited and abused by her daughter, who left her on the floor after a fall, withheld medications, and refused to feed her.
• A woman who was not believed when she reported being sexually exploited by the bus driver of an adult day service and was later asked to leave the day service.
• A woman who was alienated from her children and friends by her second husband, who repeatedly intercepted social workers' attempts to reconnect her with her family.
• A woman whose daughter stole her pension, spent $60,000 on her credit card, and arranged for her mother to write a new will where she would receive her anticipated $170,000 inheritance in advance.

St Vincent's Hospital senior social worker Meghan O'Brien, said about 65 per cent of victims were telling medical staff about their abuse.

"The hospital is a window of opportunity," she said.

St Vincent's is the first health service in Australia to collect data on cases of suspected elder abuse. It found about one third of the victims were males, 49 per cent are aged over 80 years old, and most live in the same home or are dependant on the perpetrator.

"The biggest issue is the shame and embarrassment because most abuse is being caused by an immediate family member and often they live in the same home," Ms O'Brien said.

"Very few older people want to go down a pathway to cease the relationship with that family member.

"We have to respect them and their choices and then weigh that up against the risk factors."