The army that powers the nation's workforce by taking care of its young is not so much devoted to duty, for the most part, as it is devoted to grandchildren.

Susie Balderstone begins her pilgrimage in the dark, rising before 5am at her home in MacMasters Beach on the central coast to drive to Woy Woy and catch the train to Sydney before her daughter leaves for work.

For the next two days, she looks after Matilda, sometimes sleeping on her daughter's couch overnight, other times spiriting the one-year-old back to MacMasters and returning her on Friday evening.

By the time the weekend arrives, she is spent.

But the idea of accepting money for her pains is anathema.

"I love Tilly and my days with her," Mrs Balderstone said.

"It gives a wonderful dimension to both our lives.

"I'm not doing it for money and that wouldn't be the reason I'd do it."

The Productivity Commission's draft report into childcare proposes government subsidies for paid grandparent carers.

It is a prospect that might be expected to cause an outbreak of joy among the photo-swapping set.

Grandparents were the most commonly used type of care among children aged under 12, according to a 2010 study by the Bureau of Statistics.

About 24 per cent of children under the age of two were in the regular care of a grandparent.

The work can be weary. It can restrict the spontaneity of post-working life. It entails a commitment that, if broken, arouses unjust feelings of guilt.

But grandparents said they performed it out of love, and seniors groups predicted that few would take up the offer of remuneration.

National Seniors chief executive Michael O'Neill said most grandparents willingly gave their time to provide informal care to their grandchildren.

"The value to society of that should not be diminished by a rush into paying grandparents for their services," he said.

Woollahra grandmother Louise Leibowitz, who devotes two days of her week to looking after her two-year-old granddaughter and 18-month-old grandson respectively, said she would not dream of accepting money.

"But I'm in a fortunate position where I don't have to worry about that," she said.

"There are some grandparents who couldn't afford to do what I do and in those cases they should be eligible for some compensation.

"I do it for me. I don't do it for my grandchildren, I don't do it for my daughters-in-law, I don't do it for my sons, so for me the money would taint the specialness of that. I absolutely love it."