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."
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Portman was due to receive the award in Israel in June and said that her reasons for skipping the ceremony were solely due to Mr Netanyahu.
Analysis of Department for Work and Pensions data found the average man receives £153.86 a week and the average woman receives £125.98.
The country says it is making the move to shift its national focus and improve its economy.