"The Government's welfare changes require significant up-front financial support. We've made a commitment to provide that investment to ensure fewer people are on welfare long term."
Legislation to make the changes for the first stage is currently before Parliament. The changes for solo parents will come into effect in October and for youth in July.
Under the changes, solo parents will be expected to look for part time work when their youngest child is 5 and full-time work when their youngest is 14. Those who have another child while on the benefit will have to look for work when that baby is one year old.
Young people and teen parents will have essential costs such as rent and power paid directly and get a payment card for living costs. There will also be childcare payments to allow teen parents to study or train.
The second raft of changes - which will merge benefit types into three main categories, including the 'Job Seeker Support' category for unemployed, single parents and sickness and invalids - will be funded in next year's Budget.
The total extra cost of the reforms will be $520 million over four years - more than half of the $1 billion the reforms are expected to save.