Local MP Alan Mak has urged Chancellor Rachel Reeves not to scrap the two-child benefit cap in the November budget.
He said lifting the cap would be financially irresponsible and also unfair to those who are in work and being hit by the cost of living crisis under Labour.
The cap was introduced in 2017 by the then-Conservative government as an incentive to work and restricts welfare payments to the first two children born to most families.
The Resolution Foundation think tank said axing the policy would cost £3.5bn which taxpayers would have to fund.
Last month a Bill seeking to scrap the cap passed the first stage in the House of Commons, but Mr Mak voted against.
He said: "Getting rid of the cap and allowing unlimited welfare claims would be unfair. I believe those on welfare should have to make the same responsible decisions about having children as those who are in work.
"Scrapping it would have to be paid for, meaning more taxes and more debt."
If the cap is lifted by Labour, the next Conservative government would reinstate it.
