The government is publishing its Children's Bill on Thursday - but some charities fear it will prove a missed opportunity to fully protect under-18s.
Victoria Climbie suffered horrendous abuse from her carers
An alliance of 350 organisations is calling for the bill to give children the same legal protection against assault in the home as adults.
But the government says it has no plans to scrap the legal defence of "reasonable chastisement" for parents.
The Children Are Unbeatable! Alliance says it is used to excuse beatings.
Spokesman Tony Samphier told BBC News Online: "There is nothing reasonable about so-called reasonable chastisement.
"It means children have less protection from being hit than adults, yet they are the weakest and most vulnerable members of society.
"It sends out a misleading message about the acceptability of violence towards children.
"Hitting children is wrong, and the law should say so."
The law as it stands "is out of step with modern family values", Mr Samphier added.
On Monday Parliamentary under-secretary for Early Years and Schools Standards Baroness Ashton told the House of Lords the law as it stands "reflects the right balance between protecting children and allowing parents to make their own choices about discipline in the home".
"In a loving family, there are different modes of discipline," she added.
The Children's Bill follows September's green paper from Education Secretary Charles Clarke in response to the recommendations of the
Laming Inquiry into the death of eight-year-old Victoria Climbie.
Victoria died in north London in 2000, after prolonged neglect and cruelty by her carers.
Lord Laming's report said she had been seen by various professionals who did not share information and failed to save her.
The green paper proposed the creation of Local Safeguarding Children Boards to bring together local education authorities, police, health and social services under the direction of a single official, to be known as director of children's services.
But charity 4Children's chief executive Anne Longfield told BBC News Online the structural changes would need to be backed up by "real hard cash" and the political will to make them work.
And the NSPCC charity is already warning it could take many years to introduce these "vital reforms to protect children".
Director Mary Marsh said: "All local authorities must be required, as a matter of urgency, to bring in directors of children's services to lead this change.
"Those facing abuse cannot wait for action to protect them.
"MPs and peers must not miss the opportunity to ensure help is delivered to them as soon as possible."
Ms Marsh said the bill "is a pivotal moment for the next generation of children".
"History will judge how it works on the ground to stop children being abused and sometimes killed," she added.
"No amount of structural change can replace the basic requirement for a properly resourced and trained workforce which provides all children with someone to turn to."