Jeremy Corbyn will on Saturday call the much-criticised reforms an “unmitigated disaster” as he outlines proposals to depart from a system designed to “punish and police”.
The benefit cap and two-child limit would be immediately ditched, which Labour says would bring 300,000 children out of poverty.
Charities welcomed significant reform but warned against “further upheaval”, as the Tories outright rejected the proposals.
Mr Corbyn is expected to say: “Universal Credit has been an unmitigated disaster.
“As well as being behind schedule and over-budget, it is inhumane and cruel, driving people into poverty and hardship.
“Social security is supposed to give people dignity and respect, not punish and police them, make them wait five weeks for the first payment or fill out a four-page form to prove their child was born as a result of rape.
“When a Labour government takes office we will introduce an emergency package of reforms to end the worst aspects of Universal Credit.
“We will introduce a new system that will be based on the principles of dignity and respect, and it will alleviate and end poverty, not drive people into it.”
Social security is supposed to give people dignity and respect, not punish and police them, make them wait five weeks for the first payment or fill out a four-page form to prove their child was born as a result of rape
The Labour leader will announce the plans during a rally in the Chingford and Woodford Green constituency held by Universal Credit architect and former Tory leader Iain Duncan Smith.
The plans also include ending the system’s “digital-only” requirement, which Labour says excludes people who cannot access the internet or lack computer literacy, by recruiting an additional 5,000 advisers.
The five-week wait to be described by Mr Corbyn as causing “so much misery and suffering” would also go, with an automatic interim payment and a switch to fortnightly payments.
Gingerbread backed the announcement and highlighted research suggesting Universal Credit causes housing insecurity and debt for most single parent households, like the ones the charity supports.
Chief executive Victoria Benson said: “It will be essential for any future government to take steps like these if we are to loosen poverty’s grip on huge numbers of single parents and their children.”
Food bank charity the Trussell Trust welcomed the end of the five-week wait but also warned Labour’s plans could create further problems.
Chief executive Emma Revie said: “Scrapping Universal Credit may only result in further upheaval, we urgently require reforms which put the needs of those using our benefits system at the heart of its redesign.”
The Conservatives branded Labour’s plans as “totally irresponsible”.