Lone parents are to be encouraged to return to work under government plans intended to tackle child poverty.
The rules on lone parents' benefits may be changed in a government attempt to get more back into work earlier.
Work and Pensions Secretary John Hutton says he does not want lone parents moving "seamlessly" on to incapacity benefit once their child benefits stop.
Single parents can currently receive Income Support without having to seek work until their youngest child is 16.
However, he said there was "absolutely no case for cutting lone parent benefits" as it would harm children.
But Work Secretary John Hutton told BBC Radio 4 he thought it not "unreasonable" to cut that age to 12.
Single parents receive payments until their youngest child is 16. Ministers are thought to favour cutting it to 11.
The Tories said Labour had failed over 10 years to reform welfare. The Lib Dems welcomed the move if the savings were invested in providing childcare.
But charity One Parent Families said many of those affected by the plans were caring for disabled children.
Charity One Parent Families said it could affect many parents caring for disabled children.
The Office for National Statistics estimates there are 1.69m lone parents with dependent children in the UK.
The Office for National Statistics estimates there are 1.69m lone parents with dependent children in the UK.
Low employment
In a speech, Mr Hutton said Britain has one of the lowest levels of lone parent employment in Europe, with almost half on benefits.
In a speech, Mr Hutton said Britain has one of the lowest levels of lone parent employment in Europe, with almost half on benefits.
'Child poverty'
If we are to eradicate child poverty, then I believe we will also need to go further in challenging existing assumptions about who - and at what point - someone should be in work John Hutton
He said he has evidence that up to a third of lone parents move on to incapacity benefit once their child benefit ends as their youngest reaches 16.
He said up to a third of lone parents move on to incapacity benefit once their child benefit ends as their youngest reaches 16.
Mr Hutton has already unveiled plans to to get one million incapacity benefit claimants back into work over the next 10 years, saving £7bn a year.
Mr Hutton has already unveiled plans to get one million incapacity benefit claimants back into work over the next 10 years, saving £7bn a year.
I think we need to give parents encouragement and support to take well-paid jobs if they are able to do that but to give them the choice Chris Pond, One Parent Families
"If we are to eradicate child poverty, then I believe we will also need to go further in challenging existing assumptions about who - and at what point - someone should be in work," he said.
He said: "If a person has been out of the labour market for 10 or 15 years, during which time they have had little help or support, they are obviously going to find it difficult moving straight from Income Support on to Job Seekers Allowance and being required to actively seek work.
Plans welcomed
"If we are to eradicate child poverty, then I believe we will also need to go further in challenging existing assumptions about who - and at what point - someone should be in work.
"We also know the difference that helping lone parents into work can make. A significant proportion of our progress so far in tackling child poverty is due to helping lone parents move into work."
"We also know the difference that helping lone parents into work can make. A significant proportion of our progress so far in tackling child poverty is due to helping lone parents move into work.
In countries with highly regarded welfare systems such as Sweden and Denmark, up to 80% of lone parents are in work, he said. In Britain, just 56.5% of lone parents are in work.
"Our reforms to childcare will be one crucial part of breaking down the barriers to work and helping lone parents to stay in work for longer."
For the Conservatives, shadow work and pensions secretary, Philip Hammond, said: ?Work for parents, both couples and lone parents, must be the key weapon against child poverty.
'Choice'
"Labour have had 10 years to sort out the welfare system and have failed. A last minute rush at the end of Tony Blair's reign is not going to solve the deep problems plaguing the welfare system in this country."
He said that in countries with highly regarded welfare systems such as Sweden and Denmark, up to 80% of lone parents are in work. In Britain, just 56.5% of lone parents are in work.
Liberal Democrat work and pensions spokesman David Laws welcomed the plans, but said any money saved must be used to improve childcare.
But any measure affecting lone parents could prove controversial among Labour MPs.
It does dismay me that we are still pandering to this stereotype of the lazy, work-shy, lone parent Lynne Jones MP
One of the biggest revolts early on in Labour's rule came in 1997 when 47 MPs voted against cuts in lone parent benefit.
"It is essential that single parents are supported to stay at home with young children.
Chris Pond, chief executive of the charity One Parent Families, said: "I think we need to give parents encouragement and support to take well-paid jobs if they are able to do that but to give them the choice."
"But the fact that British single parents can receive Income Support without any requirement to look for work until their youngest child is 16, is out of line with the rest of Europe."
'Inappropriate'
Labour MP Lynne Jones, who played a prominent role in the backbench rebellion when 47 MPs voted against cuts in lone parent benefits in the late 1990s, warned the plans would "cause conflict" within the Labour party.
He said 66% of lone parents with a youngest child aged between 11 and 16 were already in work and the government's target was 70%, "so this isn't going to take you very far".
She told BBC Radio 4's World at One programme: "It does dismay me that we are still pandering to this stereotype of the lazy, work-shy, lone parent who doesn't do a very good job of bringing up her children anyway."
Parents struggle
Clare Tickell, of children's charity NCH, said many parents wanted to work but struggled because of a lack of support.
"Encouraging lone parents to work is a step towards tackling child poverty but they need a package of flexible support to help them juggle the demands of family life and employment," she said.
Chris Pond, chief executive of the charity One Parent Families, said 66% of lone parents with a youngest child aged between 11 and 16 were already in work.
As the government's target was 70%, he said, "this isn't going to take you very far".
A quarter of the parents that would be affected were caring for a disabled child, Mr Pond added.
A quarter of the parents that would be affected were caring for a disabled child, Mr Pond added.
"So in those circumstances it may be inappropriate to force the lone parent to take a job which means they're not able to fulfil the caring role.
"And we may all pay a heavy price if parents of teenagers who are going through a difficult time, just going into the secondary school phase and into exams, are not given the support they need in lone parent families," he told BBC Radio 5 Live.
Are you a lone parent? Are you worried your benefits could be cut? Send us your comments and experiences using the form below.
Are you a lone parent? Are you worried your benefits could be cut? Send us your comments and experiences using the form below.
