Sir John, who sits on the new deal task force, said the connection between the minimum wage and new deal scheme was important, and it would help if rates recognised that scheme employees would be less skilled.
But he said a full job deserved a full wage and 'exceptions should be related to whether a person is in a trainee type role or not'.
Submissions to the Low Pay Commission closed this week. Its proposals will have a strong bearing on the new deal programme. The government is promising 18 to 24 year-olds 'real jobs' under the scheme, but some employers have expressed concern about affordability. Unions do not want artificial 'make-work' options but equally want to avoid subsidised workers taking ordinary vacancies.
Board of Trade president Margaret Beckett has told the commission to make recommendations on 'lower rates or exemptions for those aged 16 to 25'. Although unions reject a lower minimum wage for youth workers, they have not discounted a trainee rate.
At the Labour Party conference last month, Trades Union Congress general secretary John Monks said the TUC wanted the minimum wage to apply to all 'fully trained adult workers under 25'.
Unison head of local government Keith Sonnet said there should be no age differentiation in the minimum wage. But it was 'quite appropriate' for new deal employees to get a training allowance.
In its submission to the commission, the GMB supported a lower minimum tagged to training, not age. 'Only employees on approved training schemes should be exempted from the statutory minimum requirements and this should apply at any age,' it said.