Labour leadership candidate Yvette Cooper wants to adopt Scandinavian-style system of universal childcare, with 30 hours of free care for all preschool children over the age of two.
Writing in The Independent, Ms Cooper said she wanted to see new tax credits to help parents out in the period after maternity leave finishes, and that the pledge would be a cornerstone of her leadership campaign.
She said: "We should campaign for universal childcare - as other countries, including Scandinavia, have.
"That means breakfast clubs, after-school clubs, holiday clubs and free nursery places and childcare available full-time, not just for three and four-year-olds but two-year-olds too."
Labour leadership hopeful Yvette Cooper has said she will put measures to help families at the heart of her campaign to rebuild Labour after its election defeat.
The shadow home secretary said Labour had to "reach outwards" and "rebuild", winning back voters who deserted the party in favour of the Tories, Ukip and the SNP.
Ms Cooper believes she can smash the "glass ceiling" and become Labour's first permanent female leader, vowing to "shake up the system".
In an interview with The Sun on Sunday (£), mother-of-three Ms Cooper, whose husband and former shadow chancellor Ed Balls lost his Westminster seat in the general election, said Labour had to offer hope to families.
Yvette Cooper, the shadow home secretary and Labour leadership contender, has accused David Cameron of "taking people for fools" after new figures showed a significant increase in net migration to the UK.
Ms Cooper said there was a "massive gap" between the government's "rhetoric" on immigration and the "reality".
She said: “David Cameron is taking people for fools. On the day he has promised yet again to cut net migration to the tens of thousands, these figures show it is over three times that target.
"This massive gap between rhetoric and reality, between promise and delivery, just destroys trust in anything Ministers say on immigration."
Yvette Cooper has dodged questions about her potential leadership ambitions after a disappointing night for the Labour Party.
When asked by ITV News whether she would be standing for leader if Ed Miliband resigned, she said: "I really don't think we should be talking about this. We have just had an election and we've got a lot more election results to come.
When second journalist repeated the question, Ms Cooper said: "Seriously no there isn't one."
Yvette Cooper, Labour's shadow home secretary, has told ITV News that an exit poll showing the Tories as the largest party "just doesn't feel right".
Ms Cooper said the poll "simply doesn't fit" with what the party "felt on the ground".
"We've just got to wait till the results come in," she told Tom Bradby.
Yvette Cooper has said the country is "within touching distance" of a Labour government.
The shadow home secretary told BBC's Andrew Marr Show, "We've got four days to go and look, we are getting a very warm response.
"I think we are within touching distance of having a Labour government with a completely different vision for Britain.
"It's about our values as well as the policies we're setting out."
Shadow home secretary Yvette Cooper claimed the security services' hands were tied for nearly five years by Mrs May's "wrong" decision to scrap powers to move terror suspects away from their extremist networks.
Relocation powers have been reintroduced by the coalition this year but Ms Cooper called for the security services to immediately brief the Intelligence and Security Committee on how the loss of the measures might have affected their work.
This would allow MPs to review whether the loss of relocation powers had led to more British jihadists travelling to Syria and Iraq and more radicalisation in the UK.
Ms May told BBC1's Andrew Marr Show:
Labour's shadow home secretary Yvette Cooper believes the rape tweets directed at Jessica Ennis-Hill prove why her stance on Ched Evans is so important.
Ennis-Hill received abusive tweets from trolls on Friday after making it clear she would remove her name from a stand at Sheffield United if the club offer the convicted rapist a contract.
The tweets directed at the Sheffield born Olympic Champion are currently being investigated by South Yorkshire police.
Cooper also urged the League One club to "recognise their responsibility to the local community" by resisting the temptation to offer Evans a professional deal.
Shadow home secretary Yvette Cooper has said Labour would "look carefully" at any anti-terror proposals the Prime Minister brings forward.
"The Government should be introducing mandatory de-radicalisation programmes as a priority," Yvette Cooper said.
"Our border controls are simply not picking people up, and no new orders will change that. Only this week a suspect on bail managed to flee with his passport, reportedly to Syria, Cooper said."
“The Prime Minister would be well-advised to reinstate measures we know work, and we hope some of these changes will be in any proposed legislation.”