SOCIAL Services Minister Christian Porter has labelled the watered-down welfare reforms that were released on Wednesday by the Turnbull government as a pragmatic approach.

The changes - announced by Mr Porter, Treasurer Scott Morrison and Education Minister Simon Birmingham - scale back the Abbott government's much-maligned 2014 budget decisions to cut Family Tax Benefit Part B payments from families once a child turns six.

Under the new moves, the government proposes ending the payment for eligible families when a child turns 13.

Also, Family Tax Benefit Part A payments would be boosted by $10 a fortnight for each child up until the age of 19.

The major savings, worth about $4.8 billion to government coffers over four years, would come from scrapping two annual welfare supplements - payments that often went to those not in need, Mr Porter said.

The FTB supplementary payments, worth $1080 a child, would be phased out by July 2018, but families with a child aged younger than one year would receive an extra $1000 a year.

Although the FTB B payments would end when a child turned 13, single-parent families with children aged between 13 and 16 would receive $1000 a year - a loss of $1700 on the current payment.

Mr Morrison said the changes would save the money the government needed to fund its promised $3.5 billion childcare package.

The Greens said they would not back the cuts to welfare payments.