Legislation to ban the smacking of children in Scotland is being published at Holyrood.
The bill, lodged by Green MSP John Finnie, has been backed by the government and looks certain to pass.
Mr Finnie said children should be given "the same legal protection from assault that adults enjoy".
Other parties are expected to give members a free vote on the issue, with MSPs from across the political spectrum voicing support for the move.
However, the Scottish Conservatives said present legislation "works well because it is based on common sense, and reflects what the majority of parents want".
Adopting a ban would make Scotland the first part of the UK to outlaw the physical punishment of children, with parents in England, Wales and Northern Ireland currently allowed to use "reasonable chastisement".
At present, parents in Scotland can claim a defence of "justifiable assault" when punishing their children, although there is a bar on the use of any "implement", shaking or striking a child on the head.
Mr Finnie, a former policeman, is seeking to change that with his members' bill, which would scrap the legal defence and give children "equal protection from assault".
In a consultation run over the summer he won the backing of groups including the Scottish Police Federation, Rape Crisis Scotland, Barnardo's, the Church of Scotland, the Equality and Human Rights Commission, children's groups and the Royal College of Paediatrics.
Mr Finnie said he was "delighted" to formally bring forward the bill, highlighting the backing from charities and rights groups.
He said: "Substantial academic research from around the world shows that physical punishment does not work and is shown to be counterproductive. My bill aims to support parents to make positive choices.
"The bill will not change the way that police and social work deal with assault against children. Rather it establishes the principle that assault can never be 'justifiable'."
Mary Glasgow, of the Children 1st charity, said the bill would "amend the archaic law that gives children, the smallest, most vulnerable members of our society, less protection from physical harm than anybody else".
The Rev Dr Richard Frazer from the Church and Society Council said it was "time that we, as a society, stated clearly that physical punishment cannot be part of normal family life".
Prof Steve Turner from the Royal College of Paediatrics and Chid Health said there was "nothing I want more than for children to be protected, as adults currently are, from assault".
First Minister Nicola Sturgeon voiced her backing for the bill in her programme for government speech on Tuesday, and children's minister Maree Todd confirmed this position.
She said: "This bill sends a clear signal that all physical punishment of children is wrong. Evidence shows that this can lead to aggressive and problematic behaviour into adolescence and adulthood."
Scottish Labour also backed the move, calling it "the right thing to do", while the Scottish Liberal Democrats said "the 'justifiable assault' of children cannot be acceptable in this day and age".
The Scottish Conservatives said current legislation "works well" and is "based on common sense", but said members would be given a free vote on the matter.
A spokesman said: "In law there is, quite rightly, a very clear difference between the definitions of violent assault and reasonable chastisement.
"The former is a criminal offence punishable through the courts, the latter is a matter for parents as they decide how to discipline their children.
"Each Scottish Conservative MSP is entitled to vote with their conscience on this issue."
Others have previously spoken out in defence of the practice.
When the move was first announced, the Rev David Robertson from the Free Church of Scotland told the BBC's Good Morning Scotland programme that a ban would "criminalise good parents just for tapping their child on the hand".