A new report estimates the value of unpaid caregiving in New Zealand at more than $10 billion - or five per cent of Gross Domestic Product (GDP).

The infometrics report's been done on behalf of care groups and Business New Zealand, using government data and other surveys.

It shows caregiving for friends and family members, usually in their own homes, comes with signifcant loss of income for the more than 420,000 New Zealanders who do such work.

On average they spend 30 hours a week doing it - and they're twice as likely to be women rather than men.

Infometrics says the value to the country of such unpaid work lies within a range between about $7 billion - $17 billion.