Spending cuts could force the NHS in Wales to find savings of almost £2bn over the next five years, health minister Edwina Hart has warned.
She said the foundations were in place to continue to improve patient care and claw back more cash after £850 million was saved in the last four years.
The minister revealed that between £1.1bn and £1.9bn may have to be saved by the health service over the next five years.
She called on the NHS and council-run social services to end bed-blocking by working together more effectively in a period of austerity.
At a public services summit in Cardiff, she said £200m was saved last year, partly by reducing the length of hospital stays and cutting unnecessary admissions.
This year’s target is an unprecedented £435m - about 8% of the NHS budget.
Caring for a rapidly ageing population meant that better co-operation between the NHS and local government was vital, Mrs Hart said.
By 2031, the number of people aged 60 to 75 will have increased by a quarter and those over 75 will have increased by 75%.
An estimated £30m a year is spent on so-called delayed transfers of care when patients are forced to stay in hospital due to a lack of social care services.
Mrs Hart said: “Savings of this size cannot be sustained without creating integrated services and strong partnerships - this can only be done if the NHS and local government in Wales work together to share the challenges and solutions.
“We must avoid the sort of cost-shunting that might happen at the complex interfaces of our services.”