The NHS is using an increasing number of zero hour contracts which could lead to "casualisation" of the workforce in the health service, Labour has warned.
Almost 70,000 NHS staff are employed using such contracts, under which workers are not guaranteed a certain numbers of hours, figures suggest.
Shadow health secretary Andy Burnham raised concerns that the NHS was increasingly favouring casual contracts over offering permanent roles.
Labour's latest NHS Check report showed that in 2012/13 there were more than 67,000 NHS staff employed this way compared to 57,000 in 2009/10.
The report detailed how three-quarters of hospital trusts in England were using such contracts. It also stated that 300,000 social care workers were employed this way - 20% of the entire workforce for the sector.
The report said: "If the staff do not have the security of knowing what they will earn from week to week, they could find it harder to give a sense of security to those they care for."
Mr Burnham called on the Government to review the use of zero hour contracts and their impact on patients and older people.
He said: "These figures provide worrying evidence of the rise of the zero-hours culture in England's NHS and of the growing casualisation of the NHS workforce under David Cameron. Health and care is different from other sectors.
"Good care cannot be provided on a 'here today, gone tomorrow' basis. Services and staff need to be there for people day in, day out."
A Department of Health spokesman said: "NHS and social care organisations are independent in their own right and make their own employment decisions about their staff. But we are clear that these decisions must be based on providing the best patient care."