Ed Miliband has told supporters that the IFS assessment of party manifestos showed the Tories were committed to "extreme spending plans".
"They have also confirmed that Britain would be facing the deepest cuts over the next three years of any advance country in the world," the Labour leader said during a visit to Nuneaton in Warwickshire.
Miliband continued: "It is a plan so extreme that far from protecting the NHS they would end up cutting the NHS.
"It is a plan so extreme that it wouldn't mean three years of the good life, it would mean three more years of the hardest of times."
Ed Miliband has unveiled a new poster campaign with Labour's proposals for a "better plan for the NHS".
ITV News Political Correspondent Carl Dinnen reports from Nuneaton:
Ed Balls, Labour’s Shadow Chancellor, has defended his party's budget plans after the Institute for Fiscal Studies said voters were 'in the dark' over the plans of four major parties.
The IFS’ numbers wrongly assume that Labour will get the current budget only into balance. Our manifesto pledge is to get the current budget not only into balance but into surplus as soon as possible in the next Parliament. How big that surplus will be, and how quickly we can achieve that in the next Parliament, will depend on what happens to wages and the economy.
The Tories might be able to make the cuts but the last five years show they will fail to cut the deficit as they claim. They have borrowed £200 billion more than they planned because their
None of the top political parties have provided "anything like full details" on plans to cut the deficit in their manifestos, IFS says.Read the full story ›
None of the main political parties has provided "anything like full details" on plans to cut the deficit in the next Parliament, the Institute for Fiscal Studies has said.
Ed Miliband said his new-found sex symbol status was unlikely to worry the boy band as #milifandom takes over the internet.Read the full story ›
Gordon Brown has warned that Nicola Sturgeon's plans would leave a £7.6 billion hole in Scotland's economy, as he pitched Labour as the country's "party of fairness and social justice".
In a letter to voters, the former Prime Minister claimed both the SNP and the Conservatives would leave the NHS at risk.
He said the nationalists would "scrap the Barnett formula, meaning that our NHS and other public services could only be funded by taxes raised in Scotland."
He also warned that the Conservatives were "committed to billions of pounds more austerity - which means less money for Scotland and our NHS".
Labour would hope to begin to "phase out" GCSEs within the next 10 years, the shadow education secretary has said.
Tristram Hunt said English schools had a "long tail of underachievement" and proposed a 14-19 curriculum to replace GCSEs, as he claimed more pupils were staying in education up to 18.
But he said should he become secretary of state for education in a Labour government post-May 7, he was "not going to touch" reforms made by the Conservatives, which included a shake-up of gradings and coursework.
Labour has accused the Tories of planning the biggest spending cuts in any of the world's advanced economies since the Second World War.
Ed Miliband warned the Conservatives plan to balance the books would result in 20,000 fewer police officers and the closure of 1,000 sure start centres.
He will tell a rally in Leeds: "It is a plan so extreme that International Monetary Fund figures show Britain would be facing the deepest cuts over the next three years of any advanced country in the world.
"It is a plan so extreme that far from protecting the NHS they would end up cutting the NHS. It is a plan so extreme that it wouldn't mean three years of the good life, it would mean three years of hard times.
"Maybe not for some of the rich and powerful, who have done so well with the last five years of the Tories. But it would mean hard times for the working families of Britain, who put in the hours, pay their taxes and play their part."