Youngsters on the Government's work experience scheme will be able to leave after a week without facing benefit sanctions under a change announced by ministers aimed at heading off criticism of the programme.
The move followed a meeting with scores of employers following protests by activists who complained that youngsters were being forced to work for nothing.
The Department for Work and Pensions (DWP) said sanctions would still apply for cases of gross misconduct, such as stealing or racist abuse, but those taking part in the scheme would be able to leave after a week without losing their benefits.
Employment minister Chris Grayling described it as a "change" that would help companies, insisting that opponents were "completely misguided".
He said: "Following a productive meeting with employers I am delighted that we have pledges from some of the UK's top companies to take part in the scheme. The likes of Airbus, Centre Parcs and HP Enterprise Services will join in Voluntary Work Experience helping our young unemployed people get their first vital step into employment.
"Despite the persistent campaign of the last two weeks we have had contact with over 200 small or medium enterprises also wanting to get involved. The work experience scheme remains and is totally voluntary. The sanction regime remains in place. Employers continue to have the protection with the use of sanctions for gross misconduct.
"We have used the meeting to explain how the regime applies. It has never been an issue with the programme as only 220 people have been sanctioned since it started."
The Government launched a strong defence of the scheme, announcing that hundreds of new small to medium-sized firms had expressed an interest in taking part since controversy over benefit sanctions flared recently.
Prime Minister David Cameron told the Commons: "I think the whole country wants to see young people given the opportunity that work experience provides. I think it is time that businesses in Britain, and from everyone in Britain, who wants to see people have work experience, stand up against the Trotskyites of the Right to Work campaign and perhaps recognise the deafening silence we have had from the party opposite."
TUC general secretary Brendan Barber said: "We welcome the Government's climbdown on the use of sanctions in work experience. Of course proper work experience can be useful and helpful for many young people, but it needs to be designed to help the young person, not provide free labour for employers or displace paid staff. Making absolutely clear that it is voluntary at all times will help safeguard against abuse."