Older mixed-age couples could lose almost half of their weekly income if proposed welfare reforms come into place, Age NI told MLAs on 30 October 2012.
The charity's Bernadette Magennis was giving evidence on the Welfare Reform Bill.
If passed, the bill will bring changes introduced at Westminster, and which have marked the biggest overhaul of the benefits system since the 1940s, into effect in Northern Ireland.
One of the reforms is the introduction of the single, universal credit to replace six income-related, work-based benefits.
Ms Magennis told the Social Development Committee that under current structures, a couple aged 61 and 56, would receive £217.90 per week in pension credit.
"If the same couple were being assessed under universal credit, their income would be reduced by £102.45 a week," she said.
The Age NI representative emphasised that this was a very basic analysis which did not account for different variations, but she said it did highlight that a single person on pension credit would be better off than a mixed-age couple.
The second part of the debate can be viewed