A study by the University and College Union (UCU) found that the average weekly pay of 16 and 17-year-olds was a third less than the national average for all wages.
Young people were also more likely to be paid below the national minimum wage, the union study of official data showed.
Weekly wages for full-time workers went up by 3.6 per cent between 2009 and 2012 but fell by over 17 per cent for 16 and 17-year-olds, to an average of £161, said the report.
A separate report by The Jobs Economist consultancy said that despite the growth in employment in recent years, there had been little change to the rate at which people leave unemployment for work, which accounts for the “stubbornly high” level of youth joblessness.
Director Dr John Philpott said: “While today’s very high level of youth unemployment is undoubtedly partly related to lack of employability and skills, the bigger and more immediate cause is a simple shortage of job opportunities, the only solution to which is a further substantial boost to demand for labour.
“In the absence of this, welcome efforts to encourage employers to hire and retain young jobless people, such as the Government’s Youth Contract wage subsidies, will continue to disappoint.”