Children's welfare could potentially be at risk because of funding cutbacks to foster care, a group which represents independent foster carers has warned.
The Nationwide Association of Fostering Providers said the Welsh government consortium which buys their services is looking to renegotiate their contracts.
Philip Sutton from the NAFP said he was concerned councils, through the consortium, were looking to cut costs.
The Welsh government said it works with councils to improve foster care.
The NAFP represents independent foster carers, who provide just under 40% of placements in Wales.
Mr Sutton said he was worried children "would not thrive in the way we have expected them to" because of the cuts.
"My main worry is that local authorities, through the consortium, are looking to reduce the cost of placements by reducing the additional services that agencies provide: things like education services and respite services," he said.
"They are looking for a basic care provision."
Mr Sutton said he was also concerned that the changes might see children move frequently between placements as foster carers struggled to cope.
"One of the things we always look for in foster caring, which is proved to provide the best possible outcomes, is stability," he said.
"You need some kind of help for carers with difficult placements to achieve that.
"If foster carers are not able to access therapy or other services it can make the difference between a placement continuing or breaking down.
"The worry is if we're reducing the availability of therapy and other provisions more placements will break down and it's been shown clearly that children who have multiple placements don't do well in life generally."
Among other changes Mr Sutton said are being proposed are plans to cut the mileage allowance that foster carers can claim for trips, such as hospital appointments.
He described this as an "emotive" issue and something that some providers might find difficult to continue.
The Welsh government said it is working with councils to improve the commissioning of both local authority and independent foster care.
"Placement choice and stability are key to securing better outcomes of looked-after children in Wales," a spokesperson said.
"Local authorities must secure a range of local and independent placements to meet the diverse needs of children in their area.
"The Welsh government continues to work with local authorities in improving their strategic commissioning of placements."