Grieving communities have rallied across Queensland to remember the victims of domestic and family violence after the murder-suicide of Hannah Clarke and her three children on Wednesday.

Key points: Rallies were organised after the murder-suicide that killed Hannah Clarke and her three children

Rallies were organised after the murder-suicide that killed Hannah Clarke and her three children Micah Projects CEO Karyn Walsh says fundamental change is needed to see women and children living free of violence

Micah Projects CEO Karyn Walsh says fundamental change is needed to see women and children living free of violence Rosie Batty said more leadership needed to be shown on family violence prevention

More than 200 people gathered outside Parliament House in Brisbane to support the Red Rose Foundation and rallies were also held in regional centres including Cairns, Townsville and Mackay.

The public outpouring of grief came after Rowan Baxter doused his estranged wife and their children — Aaliyah, 6, Laianah, 4 and Trey, 3, — with petrol and set them alight in the family car in Camp Hill.

Micah Projects CEO Karyn Walsh — a not-for-profit support organisation — said the rallies provided an opportunity to raise awareness of the issue and to demand change.

"We want to make a difference. We want to see women and children living free of violence," Ms Walsh said.

The demonstrators, many dressed in black, held roses and posters with the words "DV deaths are preventable" and "25 per cent of Queensland murders are domestic violence".

Hannah Clarke with her three children, Laianah, Trey and Aayliah. ( Facebook )

'A very emotional issue'

Queensland Minister for the Prevention of Domestic and Family Violence, Di Farmer, struggled to hold back tears as she addressed the Brisbane rally.

"All around you here there are people who have been victims of domestic violence … and we all have to go away with the responsibility that we all have to actually do something about this," Ms Farmer said.

In Townsville, people attended a silent rally in the north Queensland city's main street.

Co-ordinator of the North Queensland Domestic Violence Resource Service, Mandy Thompson, said the deaths of Ms Clarke and her children had rocked the organisation.

People pay their respects to domestic violence victims at the Brisbane rally. ( ABC News: Dan Smith )

"When you hear stories like the ones that we've heard this week … it is a very emotional issue," Ms Thompson said.

"It makes us understand the serious nature of our work and the fact that we're not preventing these deaths is very sad.

"We've been trying to save women's lives forever and we feel like we're not making a difference."

Mandy Thompson (centre front) says the deaths of Ms Clarke and her children has rocked the organisation. ( ABC News: Sofie Wainwright )

She said society needed to believe women who needed help.

"We need to make perpetrators accountable," she said.

"A silent vigil is an act of respect to recognise these lives that are no longer here — they have no voice, they've been silenced forever."

Society needs to believe women, Ms Thompson said. ( ABC News: Sofie Wainwright )

'The final act of power'

Australian domestic violence campaigner Rosie Batty issued a statement in relation to the deaths of Ms Clarke and her children.

Ms Batty described the incident as "the final act of power, control and ultimate revenge committed by a family violence perpetrator".

Ms Batty, whose son Luke Batty was murdered by his father Greg Anderson in 2014, said the attack was "beyond our imagination, comprehension and understanding".

"This unspeakable act of violence should give pause for all our elected leaders to think deeply about their leadership on this epidemic," Ms Batty said.

"This is the most pressing issue of terrorism our society faces — where at least one woman each week is murdered."

There has been a public outpouring of grief over the tragedy. ( ABC News: Dan Smith )

Ms Batty added her support for changes to the family law system.

She also condemned authorities — and some media outlets — for their portrayal of Rowan Baxter as a loving father.

"A loving parent never considers murder as ever being an option or a solution," Ms Batty said.

"Murder is a decision that is deliberate and driven by the need to exact revenge and achieve the ultimate act of power and control."

Statistics show at least one woman is murdered by her current or former partner in Australia each week, one in four women has experienced emotional abuse by a current or former partner since the age of 15, one in five women has been sexually abused since age 15, and almost 40 per cent of women are subjected to violence from a partner while temporarily separated.