Yvette Cooper, one of Labour's leadership candidates, said that the government's plans for trade unions are an "ideologically driven attack on Britain's trade unions" which "puts narrow Tory party interests ahead of what is right for the country".
"It not only undermines years of progress on workers' rights, but it also breaks the growing consensus on the need to reform funding of political parties.
"This is another example of the Tories employing cheap divide-and-rule tactics."
Speaking ahead of her nomination for the race to become Labour leader, Yvette Cooper made her case in a speech in central London.
She said the leadership contest "needs to be about the future of the country not just the past of our party if we are to win again".
"We have a long, hard road to support Scottish Labour rebuilding trust in Scotland. A task to win back the trust of Labour voters who switched to Ukip, angry with us and at the world."
She added: "We won't deliver a Labour government by swallowing the Tory manifesto, Tory plans or Tory myths. In the end the Tories don't have the right values or the right answers for our country.
Labour leadership candidate Yvette Cooper has accused her party colleagues of "swallowing the Tory manifesto" since the party's general election defeat.
"I will set out ideas for the future that don't just involve swallowing the Tory manifesto and set out a Labour vision for the future," she told BBC1's The Andrew Marr Show
The comments were quickly perceived as an attack on her leadership rival Liz Kendall but when asked if she was referring to the shadow care minister, Ms Cooper said she did not want to attack specific individuals.
The shadow home secretary also appeared to criticise another leadership candidate Andy Burnham, who said that Labour had appeared "soft" on benefits claimants.
Ms Cooper said it was wrong to "stigmatise" people who were out of work, adding that it was against Labour values.
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: