Fostered children face instability and disruption due to a shortage of carers, according to a charity.
The Fostering Network wants to see a further 650 foster carers
The Fostering Network told Deputy Minister for Education and Young People, Euan Robson, that there needs to be a further 650 foster parents.
It said that while numbers are low, children will be moved from home to home.
The body fears that too many youngsters are being split up from siblings and living miles from family and friends.
The message about foster carer numbers came on the first day of Foster Care Fortnight, an annual campaign to encourage more people to become foster parents.
Statistics from the Scottish Executive show that one in four children living away from home in public care lived in three or more homes in the year ending 31 March, 2003.
This compares with one in seven children in England.
The Fostering Network's research in 2003 found that one in 10 children had lived in 10 or more homes during their time in Scottish foster care.
Bryan Ritchie, manager of the organisation in Scotland, said it is "simply unacceptable" that so many children are being moved around several homes within the space of a year.
The Fostering Network is taking part in fostering fortnight
He believes children need to be offered stability, which ultimately means having more foster carers.
Mr Ritchie said he is worried there is a lack of incentive to sign up because of the financial postcode lottery which exists in different parts of Scotland.
Mr Robson told BBC Radio Scotland: "We are trying to recruit more foster carers and I pay tribute to the 2,500 foster familes and what they are doing on behalf of society.
"We do, however, need some more. I'm not sure if 650 is the exact figure but I'll be joining with them [The Fostering Network] later on Monday to launch a recruiting drive for this year.
"It is exceedingly important that we do increase the number of families involved."