"How do you achieve cuts which minimise the impacts on families?" ... Minister for Family and Community Services, Pru Goward.

THE federal government has rejected a proposal from the NSW Community Services Minister, Pru Goward, to compel birth parents to pay child support to foster carers and condemned her ''slash and burn'' approach to policy making.

The Herald revealed yesterday that some foster parents in NSW were considering giving up their children after cuts were made to state allowances that would leave many families more than $200 a week worse off.

The allowance reduction was criticised by the federal Minister for Families, Jenny Macklin, and Minister for Community Services, Julie Collins, yesterday, who also rubbished the idea of extending child support payments to foster carers.

In December Ms Goward urged grandparent carers to seek child support payments from their children to help raise their grandchildren, which is possible under existing law but was not previously encouraged. She also wrote to the federal government asking it to consider allowing all foster parents to seek child support.

In a joint statement, the federal MPs said the state government's move was putting pressure on the ''sometimes strained relationships'' between grandparents and their children.

''These are just more cost-cutting exercises from Pru Goward, who is feeling the heavy hand of Barry O'Farrell on her department's budget bottom line,'' the statement reads.

''We understand that it is not always in the child's best interests for grandparent carers or foster carers to apply for child support.''

On January 1, the O'Farrell government reinstated a pre-2006 policy of reducing foster care allowances when children turn 16 by the same amount as a Youth Allowance payment, which the teenagers can apply for instead. The policy means carers can also lose their family tax benefit.

Ms Goward defended the move yesterday, arguing it was the fairest cut possible.

''Everybody knows I've got a $1.9 million budget gap. How do you achieve cuts which minimise the impact on families? You do something where they pick the money up from the Commonwealth,'' she said.

The opposition's community services spokeswoman, Barbara Perry, said the request for cuts to allowances had eroded carers' trust in the minister.

''The best interests of the child has always got to be paramount, not a grab for a negligible amount of savings,'' she said.

Ms Goward also defended the suspension until July of the department's VisionCare program, which provides free spectacles to the elderly and people on low incomes, saying it had exceeded its budget for 13 of the last 14 years and was draining money from out-of-home care.