Public hearings of Australia’s first royal commission into family violence begin in Victoria on Monday, with day one focusing on the core questions of who experiences family violence and what drives it.

Each day of the hearings, to run across 20 days, will focus on a different aspect of family violence, with financial abuse; perpetrator interventions; Aboriginal and Torres Strait Islanders; alcohol and drugs; police responses; and the role of the health system among these.

Commission staff have organised extra “overflow rooms” alongside the main hearing room inside the old coroner’s court building in Melbourne in anticipation of strong public interest.

The commission is being led by Justice Marcia Neave, who retired from her position as a reserve judge with the supreme court to take on the role. As the foundation chair of the Victorian Law Reform Commission, Neave is experienced in conducting inquiries into sexual offences, homicide and disability and is widely respected in the sector.

Over the next month she and her assistant commissioners will hear from expert witnesses from a range of institutions who respond to family violence, including hospitals, courts, homelessness services, refuges and police.

Following opening statements from Neave and her staff on Monday, evidence will be given by the assistant commissioner of Victoria police Wendy Steendam and the CEO of Good Shepherd youth and family service, Rhonda Cumberland.

On Tuesday, the commissioners will hear from those who work with and respond to child victims.

While a few victims of family violence will also provide statements throughout the public hearings, the bulk of the witnesses are experts tasked with responding to violence and assessing risk.

This was because, the government has said, the scale and severity of family violence had already been well-established and there was no need for victims to prove this, though they were encouraged to provide submissions and attend private hearings.

There was also a need to ensure the commission did not go any longer than necessary so change could begin as soon as possible, the government has said.

The royal commission’s aim was not to apportion blame to individuals. Rather, the terms of reference states the commission must evaluate gaps in responses to family violence across the system and make recommendations for stronger responses and prevention.

The Victorian premier, Daniel Andrews, officially launched the commission in December following a spate of horrific murders of women and children across the state. Family violence was the leading cause of death and disability in Victorian women under 45 and cost the economy more than $3bn each year, the government found.

An independent inquiry by a royal commission was needed in response to a broken system which neither punished the guilty nor protected the vulnerable, Andrews said at the time, describing family violence as a national emergency.

While some experts feared the commission would mean other, more immediate responses to family violence may be delayed, most have welcomed it as an opportunity to give prominence to the issue and add weight to measures already suggested to tackle it.

To date, the commission has received more than 1,000 written submissions and has held 43 consultation sessions at 21 locations throughout the state. These, along with the public hearings from Monday, were to all help inform its recommendations, expected to be handed down in December.

Every recommendation would be adopted, the government promised.

The National Sexual Assault, Domestic Family Violence Counselling Service can be reached at 1800 737 732

The Men’s Referral Service provides anonymous and confidential telephone counselling, information and referrals to men to help them take action to stop using violent and controlling behaviour: 1300 766 491