The criticism follows research showing children who grow up in poverty are more likely to face hardship themselves when they grow up.
The conference held by One Plus, the UK's largest lone parent organisation, heard calls for cuts in local government funding to be restored to help lone parents beat the poverty trap.
There is concern that, despite the government's promise of a "war on child poverty," little has actually changed.
Benefit levels
Apart from the decision to alter benefit levels for single parents, cuts in local government funding mean there is less money at community level to support one-parent families.
Research from the Joseph Rowntree Foundation suggests children of single parents, and in poverty, are less likely to escape from poverty themselves when they grow up.
One Plus says that, although the government focus is now on helping the unemployed back into work, local authorities have less money available for childcare - an acute difficulty for lone parents.
The organisation says there appears now to be little official recognition that some parents need to stay at home to look after their children, without being labelled "work-shy".
One Plus director John Findlay said: "The day-to-day experiences of Scottish children in one parent families highlights the many pressing problems which must be tackled if the government's pledge to end child poverty within 20 years is to be fulfilled.
"Children who grow up in poverty are most likely to face social exclusion when they become adults.
'Major issue'
"The fact that so many children in one parent families live in poverty is a major issue facing policymakers.
"The Scottish Parliament, with responsibility for health, education, training policy, social work, housing and economic development will make key decisions about many areas of life which affect children in low income families.
"If government policy fails to address lone parent poverty, the idea of eradicating child poverty in 20 years will be an impossible dream."