She left him the same day. Julie wasn't permitted to visit her three-month-old son and toddler daughter for another month – until her facial swelling subsided.

But she recalls squealing with delight when told by Family and Community Services that she would be referred to a family restoration program, called Newpin (New Parent and Infant Network).

"This was my chance," she says.

Unlike regular contact visits, where government workers scrutinised her interaction with the children, Newpin seemed like a regular parenting group, she says.

"But with a lot of support, and where everyone is in the same situation," Julie says.

"In society, if you mention DOCS, people freak out and assume you are a bad parent. It is so comforting to walk in and know we are all in the same situation," she says of the St Marys' centre she continues to attend with her children three days a week.

Kids play, eat together, and mums talk. Beating expectations, Julie's children were returned by court order after seven months of attending the program.

They are among the 66 returned children, and 35 families who successfully prevented their children from entering care, that have triggered a payout to private investors under the Baird government's financial experiment of Social Benefit Bonds.

The first in Australia, the $7 million bond was issued to investors in 2013 with the purpose of expanding Newpin, which is run by UnitingCare.

New bonds will soon be issued for youth homelessness and prisoner reoffending programs, and Premier Mike Baird told a New Zealand audience this week he wanted to tackle obesity through a bond later this year.

Announcing this year's results of the Newpin bond – a return of 8.9 per cent to investors – NSW Treasurer Gladys Berejiklian said the bonds were the "cutting edge" of finding new ways to tackle social challenges.

"This model has allowed us to tap into new sources of funding so that we can deliver better social outcomes for those most at-risk in our community," she said.

Ian Learmonth, of Social Ventures Australia, which raised the $7 million from investors for the Newpin bond, says they are typically superannuation funds with a focus on ethical or social outcomes, foundations and high-net-worth individuals.

"This isn't about giving money away, but making sensible investments where you can identify some kind of social outcome," he said.

Bob Mulcahy, UnitingCare operations director, said other states are now considering emulating the Newpin program.

The upside for the government, which pays a dividend to investors each year depending on Newpin meeting family restoration targets, was saving money over the long term, he said.

"Families in Newpin have over generations had problems with drugs and alcohol, and domestic violence. If you can break that intergenerational transfer of bad habits, ultimately governments have less people in juvenile justice, unemployed and drug and alcohol programs."

Mr Mulcahy says the Children's Court, FACS and Deloitte are looking over Newpin's shoulder to independently verify outcomes.

A new centre opened at Wyong this month, with Newcastle coming next. The aim is to restore 700 families over seven years.

UnitingCare said the family restoration rate from Newpin was 62 per cent. Families Minister Brad Hazzard said this was "vastly higher" than the standard 25 per cent.