Audit Scotland criticises social care service plans
Councils and health boards are failing to ensure vital care services can be delivered in the future, Scotland's public spending watchdog has warned.
Spending cuts and an ageing population mean the cost of caring for older and vulnerable people is climbing.
But Audit Scotland said local authorities and the NHS had been slow to address the issue through "strategic commissioning".
Scottish ministers said social care resources must be better used.
Labour said the situation was a "damning indictment" of SNP "complacency" on social care.
Care services, which are currently provided by local authorities at a cost of £3bn a year, aim to help a range of people, including pensioners, children at risk, people with mental illnesses and addicts.
Last year, the Scottish government announced plans to integrate health and social care for adults and, in a new report prepared for the Accounts Commission, Audit Scotland warned the cost of running the system as a whole would more than double in the next 20 years, if reforms were not made.
The report said councils and NHS boards had been "slow" to develop strategic commissioning, with just 11 of the 32 local authority areas commissioning strategies covering all social care services.
Audit Scotland also said most of the strategies it investigated had not looked at local needs or the costs and capacity of in-house and external providers to meet them.
The report added: "We found little evidence in our audit of significant improvements and limited progress on joint commissioning by councils and NHS boards."
The watchdog also raised concern that councils were focusing on those in need of more intensive support, as well as tightening who was eligible for help and increasing charges, at the expense of others.
Accounts Commission chair John Baillie said: "Social care in Scotland faces a number of challenges.
"As budgets come under growing pressure, there are signs that councils are concentrating resources on people who need intensive support.
"There is a risk that people who need a small amount of support may not get the help they need to live independently.
He added: "Their early problems may worsen more quickly without this help and this may lead to greater cost over the longer term."
The report acknowledged strategic commissioning and joint working was complicated, but was vital, especially as the number of older people in Scotland is expected to pass the one million mark in the next decade.
It also warned councils and NHS boards needed more help to improve and that they did not have enough information to make informed decisions about allocating combined resources.
A Scottish government spokesman said: "We recognise that we must always strive to continually improve the delivery of care and that we need to make better use of the resources we commit to health and social care in Scotland.
"We are working to integrate adult health and social care and are working with partners in the NHS, local government, third and independent sectors and professional bodies to develop detailed consultation material for public discussion.
"We want to deliver the highest quality social care in Scotland that is as flexible and responsible as possible to an individual's needs. We are committed to introducing a self-directed support bill to help give people a bigger say in which social care services best suit them."