The research compiled by Methodist Church based charity Action for Children and Carers Trust revealed 700,000 under-18s look after family members who are ill, disabled, or have mental health problems.
It also found some children as young as five are helping with housework, cooking and washing.
Rossanna Trudigan from Action for Children told Premier why summer holidays are particularly difficult for young carers.
"Summer holidays could be absolutely heart-breaking for young carers," she said.
"While they're trapped inside performing caring responsibilities for a relative who might have a disability, illness, mental health problems or even an addiction, their school-friends are out having fun and socialising."
Half of under-18s who look after a family member say it's taking up four hours a day.
A poll of 270 young carers found one in five had never been on holiday with their family and 68 per cent feel stressed or worried during the holidays.
A further 57 per cent said they worry about having to tell school friends what they did in the summer break when they go back to school.
The charities have called on the government to fund council support services and access to respite support for young carers during school holidays.
Listen to Rossanna Trudigan speaking with Premier's John Pantry and Rosie Wright:
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