On Sunday, thousands are expected to walk around Lake Burley Griffin in memory of Tara Costigan, 28, who was killed late last month. It's a walk done in Tara's name, but in solidarity with all those who fall victim to family violence.

It has grown from a handful of mothers to an "immense" event of roughly 2500 people, something that has amazed organisers and touched the hearts of the Costigan family.

Michael Costigan, Tara's uncle, stood at the walk's start point near Regatta Point on Wednesday, a new tattoo reading "together we are strong" on his arm.

"The support here is, it's breathtaking, it's just beautiful," he said.

"The sense of community that's come out of this is just astounding."

His family are determined to bring something positive from Ms Costigan's killing, and are in the process of setting up the Tara Costigan Foundation to lobby, educate, and raise awareness of family violence.

For Mr Costigan, it is a form of therapy that helps him and the family deal with unimaginable grief.

"We just have waves of sadness that come over you, and it's a little bit like a rip. The only way to safely get out of the rip is to swim with the rip," he said.

"If you fight it, it remains so clear and focused in your mind that it will just drown you with emotion."

Their efforts come as support services such as the Domestic Violence Crisis Service, refuges, community legal centres, and Legal Aid warn of a rising demand for their services, which are stretched increasingly thin by stagnant or cut funding. It also comes as the YWCA Canberra call for ACT funding for a primary school-based awareness program to change attitudes to violence in the long term.

Mr Costigan believes the current debate will help usher in a generational shift, and has promised to keep asking questions of the system until the answers become clear.

"I believe this could be one of those times in the process of dealing with domestic violence, where we may actually see a coming together of people to really say 'OK, let's stop talking about it, let's do something'," he said.

A GoFundMe page set up after Ms Costigan's death on February 28 has now raised more than $100,000 for her two young boys and baby daughter.

Sunday's walk will help contribute to that, and organiser Jennelle McAppion hopes it can add another $50,000.

She said it had started as something between her and and handful of others from a Facebook mums' exercise group, which Ms Costigan had joined just five days before her death.

Interest grew, and it was made a public event, drawing 1200 participants on Facebook within 24 hours.

The Rural Fire Service have offered a fire truck for children, the Navy will provide volunteers, the Kulture Break dance crew will perform, St John Ambulance have donated their services, and Coates Hire has provided barbecues and gas, Remondis donated bins, and others have given food.

The Costigan family and others will speak and doves will be released in Ms Costigan's memory.

"It's so sad that it takes such a tragedy for it to happen, but it's really restored my faith ... I'm super proud to be a Canberran," Ms McAppion said.

There's only one way the Costigan family can describe how they feel about what has happened since domestic violence robbed them of their "angel".

"We as a family feel incredibly loved by Canberra," Mr Costigan said.

The first Walk For Tara will start at 10.30am on Sunday, at the base of the Regatta Point, Commonwealth Park West on RG Menzies Walk.