The findings are from research by Early Childhood Australia, commissioned by the office of the Opposition Leader, Tony Abbott.

The Coalition has promised a Productivity Commission inquiry into the childcare sector if elected.

"Having trained teachers working with preschool children (aged three to five) for a substantial amount of time [is] linked specifically with improved outcomes for children's literacy and social learning at age five," the research, which was given to Mr Abbott's office this month, said.

Early Childhood Australia said more highly qualified staff were paid more, and therefore more likely to remain in the sector. Stability of care is crucial for young children forming secure attachments and not developing behavioural problems.

"Infants and toddlers do not thrive in environments where their need for individualised, responsive attention and attachment with caring, consistent educators is compromised because there are insufficient skilled adults to meet these critical needs," the ECA brief stated.

The benefits to children of having more and better qualified childcare staff are being scrutinised amid the childcare union's push for a taxpayer-funded $10-an-hour pay rise, and the introduction of new childcare regulations that require higher staff-to-children ratios, and higher educational qualifications.

While childcare usage has grown 10 per cent in the past year, and Sydney parents now pay as much as $160 a day for care, the workers entrusted with their children make less than $20 an hour. A childcare worker with a Certificate III qualification earns $18.58 an hour.

Only hairdressers, animal trainers and supermarket checkout operators earn less than childcare workers, according to the latest Bureau of Statistics figures. Full-time childcare workers earn $811.40 a week, compared with the average full-time weekly earnings of $1122.60, forcing many to take on second jobs to make ends meet.

The United Voice union says one in six childcare workers will quit the industry this year knowing they can make more cleaning houses or stacking supermarket shelves. Yet no one in the sector believes parents could afford the rise in fees necessary to fund a decent childcare wage.

Kay Doyle, who pays above award wages to staff at her private centres in Lane Cove and Frenchs Forest said that, to be able to pay another $10 an hour for an educator, she would have to charge parents 50 per cent more in fees.

"I don't believe they can afford that,'' she said.

The national convener of Australian Community Children's Services, Prue Warrilow, said raising fees to cover a wage increase could force women out of the workforce.

"It becomes a choice between do you stay in the paid workforce or does the secondary income earner, usually female, have to leave the workforce?" she said. "It's a workplace productivity issue the government hasn't grappled with."

THREE JOBS TO LIVE

EIGHTEEN months ago Kate took a 50 per cent pay cut to work in a childcare centre. After six years of private nannying she wanted to help more children - but she didn't realise how much she would sacrifice going from earning more than $1000 a week to taking home $600.

''I've always loved working with kids. I've always known it was my calling,'' the 27-year-old said.

Kate has had to move in with a flatmate, give up her gym membership, cut back on travel, and take on two extra jobs to make up the shortfall in her wages. On top of her 40-hour working week at a Strathfield childcare centre, she washes dishes three nights a week at a cafe and works 10-hour days on the weekend as a nanny for four boys.

''I've gone down to basic living levels,'' Kate said. ''My friends are getting married, buying houses, travelling overseas … I'm so much behind.''

Kate can already foresee quitting the sector. She hopes the degree in early childhood she is studying by correspondence will lead to more lucrative work.