A group of 11 MPs have supported an early day motion tabled by independent MP Stephen Lloyd asking the government to reverse the announced changes to pension credit.
Pension credits used to be available to pensioners who reach state pension age regardless of the age of their partner.
But in January, Guy Opperman, minister for Pensions and Financial Inclusion, announced that new pensioners whose partners were younger than the state retirement age of 65 could no longer claim a pension credit.
Under the new rules, which will be introduced from May 15, pension age partners will be forced to claim working-age benefits alongside their younger partners.
"Pension credit is designed to provide long-term support for pensioner households who are no longer economically active. It is not designed to support working age claimants," Mr Opperman said in a written ministerial statement at the time.
Later that month he revealed the estimated saving from the policy change was close to £400m over the space of three years.
According to Mr Lloyd, the financial changes are significant because the affected couples will receive universal credit instead of pension credit.
He said: "If changes to pension credits are introduced, many citizens could be over £7,000 a year worse off.
"Much has been done in recent years to address the issue of pension poverty, with the pensions triple lock and the pension freedoms, but these changes are a backward step and, frankly, a disgrace."
Most of the MPs backing the motion are from the Labour Party, alongside one Liberal Democrat, two independent MPs, and one MP from Plaid Cymru.