A fresh squeeze on benefits will be introduced "within the first few days" of a Tory general election victory, David Cameron has promised in the latest round of campaigning ahead of May's poll.
The Prime Minister last year said that he wanted to reduce the annual benefits cap introduced by the coalition from £26,000 to £23,000 to provide another £135 million towards funding three million apprenticeships by 2020.
Regulations to tighten the limit - which are expected to mean an additional 40,000 households seeing a reduction in state help - would be among the first priorities of a Conservative administration, he has indicated.
The maximum loss - on top of the effects of the existing cap - would be £60 a week, with an average weekly loss of around £40 or £25 for those newly capped.
Another £120 million would come from removing housing benefit from 18 to 21 year olds on Jobseekers' Allowance.
Mr Cameron said the introduction of the cap in 2013 had caused a "stampede to the job centre" as the message was sent out that benefits were a safety net, not "a lifestyle choice".
"This tells you everything you need to know about our values. Conservatives believe we should be giving people the chance of a better future while encouraging people on benefits back into work," he said.
"We want to put people's hard-earned taxes into lifting people up, not holding them down. Over the next five years millions of young people will get a decent start in life, learning a trade, and knowing the purpose and pride that comes with that."
The rest of the £300 million-plus cost of the scheme - around £75 million - is expected to come from "benefit savings as young people move into work more quickly", the Tories said.
The PM also warned voters there was no need in the UK to take the sort of "risk" Greece has of electing a left-wing, anti-austerity party.
Asked in an interview with The Telegraph what influence the Greek vote could have in this country, he said: "People will take a risk when you're facing failure.
"But when it's becoming increasingly clear that we've got strong economic growth, jobs being created, Britain a destination for investment, rising living standards - when those things are clear don't risk it by scrapping the plan.
"Particularly when the people who are asking you to scrap the plan are the people who got us into the mess in the first place. And the things that they are suggesting - borrowing, spending, debt - are exactly the things that got us into trouble in the first place."
Shadow work and pensions secretary Rachel Reeves said: "Labour supports a cap on benefits. We will ask an independent commission to look at whether the cap should be lower in some areas.
"But David Cameron can't hide from the fact that his government has spent £25 billion more than planned on welfare because of his failure to tackle the low pay that leaves millions dependent on benefits to make ends meet.
"And nobody will believe promises on apprenticeships from a government that had seen the number of apprenticeships for young people fall."
In response to the Tories' plans to cut housing benefit for 18 to 21 year olds, a Liberal Democrat spokesman said: "The Tories are reverting to type as we approach the election and this is just the start.
"They have been clear they want to balance the books on the backs of the working age poor and are now proposing to slash housing benefit for 18 to 21 year olds alongside their plans to cut £12bn from working age welfare.
"This policy is as wrong as it is mean spirited and shows that you cannot trust the Tories to treat people fairly. In coalition we have stopped the Tories having free rein to cut as deeply as they would want to, and it is only the Liberal Democrats that voters can trust to build a stronger economy and a fairer society where there is opportunity for everyone."