Apprentices under the age of 19 and older workers in the first year of an apprenticeship are exempt from the national minimum wage.
The increase has been made in part to attract more young people into apprenticeships. Although the overall numbers of people joining apprenticeship schemes have risen, the figures have been boosted by the over-25s.
Among 16-18-year-olds, there has been a drop of 8.3 per cent for the year 2008-09 in those opting to join a scheme, while the proportion of young people aged between 19 and 24 taking up an apprenticeship has declined by 2 per cent.
Brendan Barber, the TUC general secretary, said: "The majority of apprentices are paid well above the minimum rate. But for many trainees, particularly young women, struggling on around £80 a week, an extra £15 will go a long way.
"The next move must be to protect apprentices with the minimum wage. At a small cost to employers, this would improve the reputation of apprenticeships and encourage more young people to enrol.