The family said the generosity and spirit of Canberra had helped support them through their grief, but the community needed to keep lobbying, fundraising and fighting to stop more unnecessary deaths.

The call came as thousands of Canberrans rallied to show their abhorrence of domestic violence at the inaugural Walk For Tara on Sunday morning.

An estimated 5000 supporters flocked to Lake Burley Griffin to march from Regatta Point to remember Ms Costigan, who was allegedly murdered by her ex-partner last month.

The 28-year-old mother-of-three was one of three lives tragically cut short, allegedly due to domestic violence, in the ACT in the past month.

Nathan Costigan, Tara's cousin, said at first it had been expected the walk would attract a turnout of 30-40 mothers.

He said the mammoth crowd had shown Canberra would not tolerate violence in the home.

"It's been unbelievable. It's been a lot bigger than we originally anticipated," Mr Costigan said.

"If there is one good thing to come from this, it's that it's raised awareness of domestic violence.

"It's pretty clear from the big show today that Canberra won't tolerate domestic violence."

But Mr Costigan urged the community to keep raising their voices against the violence, and to not forget about it once they returned home from the walk.

The Canberra Times has revealed support services – such as the Domestic Violence Crisis Service, refuges, community legal centres, and Legal Aid, which are stretched thin by funding cuts – are facing rising demand.

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.

"We need to keep up the lobbying and fundraising and be as loud for as long as we can," Mr Costigan said.

"Three weeks ago we didn't have much time to do that, but now it's the position that the family has been put in, and we're obliged to make sure this doesn't happen to other families.

"Other families should not have to feel or go through what has happened to our family.

"We can do that with community support, and over the last three weeks it has been absolutely unbelievable."

A GoFundMe page set up after Ms Costigan's death has now raised more than $105,000 for her two young boys and baby daughter.

Walk organiser Jennelle McAppion said thousands more would be added to that total as a result of the event.

"Everyone was just flabbergasted by the amount people donated," Ms McAppion said.

"It was really magical to see everyone uniting for Tara and her children, and rallying against domestic violence.

"The spirit of Canberra really came out today and it showed just how generous people are."

The walk was not the only event over the weekend, with a Friday night cruise organised by the Just Cruisin Car Club raising $1800 for both the Costigans and the White Ribbon Foundation.

Organiser Daniel Nash said the weekly cruise would normally include about 30 cars.

But Friday's event attracted about 280 cars, with participants travelling from Sydney and Cooma to take part.

Mr Nash said more than one kilometre of blue-and-white ribbon had been used to decorate the cars, along with custom stickers for the event.

The 21-year-old said he had been inspired to host the event after witnessing the generosity of the Canberra community since Tara's death.

"Everyone dug deep and were super stoked on it," Mr Nash said.

Donations can still be made at gofundme.com/nip4f8.

Support is available for anyone experiencing domestic violence by calling the Domestic Violence Crisis Service 24-hour crisis line on 6280 0900.