A leading union is stepping up a campaign to make sure interns are paid at least the national minimum wage.
Unite said the Government should do more to help stamp out "rampant exploitation" of young people as it announced moves to make it easier for people to report confidentially employers who do not pay interns.
Under the web campaign, people will be able to send information to HM Revenue and Customs, which has responsibility for enforcing the minimum wage.
Unite national officer Sally Kosky said: "We need assistance to stop employers who are failing to pay interns the wages that they are legally entitled to, and we want ministers to act to stamp out this rampant exploitation in a difficult jobs market.
"We are concerned that so-called internships replace paid entry-level jobs and are increasingly widespread among charities.
"By not paying interns, organisations are excluding many high-quality applicants, undermining ethical aims of the sector and equal opportunity in the economy as a whole."