A study by the University and College Union (UCU) found that the average weekly pay of 16 and 17-year-olds was a third of 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% between 2009 and 2012 but fell by over 17% for 16 and 17-year-olds, to an average of £161, said the report.
UCU general secretary Sally Hunt said: "Young people have been the unacknowledged victims of the recession, with those in work seeing their wages fall and those out of work seeing their opportunities reduced.
"Secure, decently paid jobs are critical to solving the crisis of youth unemployment. Research shows that most young people are desperate to work. Falling wages and little job security create a spiral of alienation and underachievement.
"Government, businesses, councils, schools and colleges and universities need to work together to help our young people to deliver a well-rewarded labour market, and high-quality education and training."
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."
Meanwhile, a survey of 2,000 people aged 16 to 24 for restaurant giant KFC found they were "remarkably upbeat" about their long-term prospects.
Two-thirds of those polled by The Work Foundation said they felt confident about their future work prospects and 63% believed they will eventually find their ideal job.
The report said that despite the optimism, young people were being let down by a shortage of support services to help them find work.
Dr Benjamin Reid, senior researcher at The Work Foundation, said: "Despite the current grim labour market, young people in the UK have high but also realistic and grounded aspirations for their careers.
"But it is equally clear from the survey that young people require a great deal more support, from business, schools and government working together, if they are to realise those aspirations."
KFC managing director Martin Shuker said: "Young people's job chances are affected by the education they receive, by the Government services in place to support young people into work, and by the attitude and engagement towards them of businesses that must provide employment.
"The better these three work better together, at the national and local level, the better prepared young people will be as they make the transition from education into work and into meaningful careers."
The research was published ahead of new unemployment figures today.