Minister for Disabled People, Esther McVey, has told Daybreak that the changes will focus benefits on those who need them most.
She said: "Disability Living Allowance (DLA) came out in the 1990s and it was very much about physical disabilities.
"Now we're adjusting it to take into account disability how we understand it today - mental disabilities as well as fluctuating ones.
"So it is actually understanding disabilities more and it is really focusing benefits to where it's needed most."
More top news
Students and staff at the American University of Afghanistan are reportedly trapped inside after militants stormed the campus.
Crisis talks are being held over fears that trainee Catholic priests in Ireland are using the gay dating app Grindr.
Greg Clarke has been named as the new chairman of the Football Association, it has been confirmed.