Corby and East Northants MP Andy Sawford said thousands of families in the constituency who receive working tax credit will be hit by a benefits cap.
The MP was speaking ahead of the vote in the House of Commons today (January 8) on the Welfare Benefits Up-rating Bill.
It will mean benefits would rise by only one per cent for the next three years, resulting in a saving of £3.7bn.
Analysis of the bill by the Institute for Fiscal Studies found that half of working-age households with someone in work would be affected in some way.
The average loss would be £165 a year for seven million families, compared with around £215 for the 2.5m workless households hit by the cap, the institute said.
Mr Sawford said: “In Corby and East Northamptonshire there are 9,300 families who receive working tax credit.
“These are middle and lower income working families who will lose hundreds of pounds under the Government’s real terms cuts to tax credit and other benefits.”
He said those in the constituency who would lose out include teachers, nurses and soldiers.
The Labour MP added: “We do need to reform our welfare system but our focus should be on helping people into work, that’s why I am backing a jobs guarantee for the long-term unemployed.
“At my surgeries I am seeing people who are working and who are at the end of their tether, struggling to buy food and heat their homes.”
The vote is expected to take place at 7pm.