The Government has faced cross-party criticism over changes to bereavement benefits, with peers urging ministers to think again.
Tory former pensions minister Baroness Altmann led demands at question time, while acknowledging the old system needed modernising and the new scheme had "some advantages".
But she said the reforms were designed to "cut" £100 million from welfare spending for bereavement, and bereaved partners without children would get more "at the expense of significantly reduced support for those with young children".
Lady Altmann asked: "What is our national insurance welfare state for if not to support families properly in such tragic circumstances?"
She urged ministers to reconsider the reforms by "extending support for bereaved children beyond the inadequate 18 months".
Work and pensions minister Lord Henley said the new Bereavement Support Payment was intended to help people with the immediate additional costs of bereavement.
It would not be taxed and would be disregarded for income-related benefits to help those on the lowest incomes most.
Lord Henley said the Government had consulted on the changes, made amendments to the regulations before they were introduced and would review them in due course.
The new Bereavement Support Payment will replace a suite of bereavement benefits and provide bereaved parents with an initial lump sum and up to 18 monthly payments.
Under current legislation, widowed parents can receive payments until their youngest child leaves school.
Former England football captain Rio Ferdinand, whose wife Rebecca, the mother of their three children, died in 2015 aged 34 after a battle with breast cancer, said recently the Government is "wrong" to cut back on the length of time widowed parents can receive bereavement benefits.