The number of children being sent to private tutors in the UK is increasing, but according to Gail Larkin - president of the National Association of Head Teachers (NAHT) - up to two hours of academic coaching after school hours is "like child abuse".
Last year, a study revealed that one-quarter of parents now pay for tuition, usually to prepare their children for school entrance exams. This figure marks an increase from 18 per cent of parents paying for tuition five years earlier.
In an interview with the Telegraph, Ms Larkin criticised the tutoring company Explore Learning, that has numerous branches inside shopping centres, high streets and Sainsbury's stores.
She said that the initiative has made after-school and weekend tuition more socially-acceptable for parents, but believes children would benefit most from activities such as swimming, football, ballet classes, or simply playing in the park.
However, Bill Mills - chief executive of Explore Learning - rejected Ms Larkin's claims and said: "Explore succeeds best when it not only helps children directly but also helps them to thrive at school.
"It is not just, or even mainly, academic progress that matters most, but also the personal development of children, including gains in confidence, enthusiasm for learning and self-esteem."
But Ms Larkin insisted that the key to a child's success is through support from parents, even if they lead busy lifestyles.
At the start of next year, the NAHT will provide a series of leaflets to parents that will offer advice about how they can help to educate their child outside of school.
This will be particularly beneficial to parents of children with special educational needs (SEN), such as dyslexia and dyscalculia - who typically require additional support, so as to not fall behind their peers without SEN.
One supportive technique parents can employ is assistive technologies. These are digital software tools designed to boost the numeracy and literacy skills of youngsters with learning difficulties.