Funds committed to reforming adult social care in England have been cut by 58%, according to the National Audit Office (NAO).
More than £1bn of the £1.74bn agreed with the Treasury for system reform has been diverted to other care priorities.
The watchdog says the government has "scaled back" its plans and is "behind schedule even on its revised plans".
The government says it remains committed to reform.
The National Audit Office is the UK's independent public spending watchdog, and holds the government to account through its audits.
According to its report, the Department of Health and Social Care (DHSC) may now only spend £729m on its planned system overhaul until 2025.