The NHS could claim back over £150m a year for treating employees injured at work, the government has said.
The scheme would apply to workplace injuries
The money would be recovered from insurance companies in cases where personal injury compensation has been paid to workers.
Hospitals can already recover costs from insurance companies for treating patients injured in road accidents, which nets the NHS around £115m.
The insurance industry said companies' premiums may already have increased.
The scheme, which will apply in England, Wales and Scotland, comes into force on Monday.
It allows the recovery of the cost of both hospital treatment and ambulance care.
Health Minister Andy Burnham said the NHS Injury Costs Recovery scheme was based on the legal rights of the NHS.
"Although this scheme will undeniably raise useful additional sums of money for hospitals, it is not simply about raising more cash.
"It is based on the legal rights of the NHS and the responsibilities of those to blame.
"We hope it will act as an additional impetus to improving health and safety.
"It is unacceptable that taxpayers have to pay for the medical treatment of someone injured at work simply because employers fail to take adequate steps to protect their workforce."
He added: "Individual hospitals will now be able to recover the costs and decide where they want to reinvest that money to improve services they want."
Malcolm Tarling of the Association of British Insurers (ABI) said companies had been preparing for the introduction of the scheme for the last 18 months.
"This has given the industry time to assess the impact of the change on their own business, so premiums may already have gone up."
He added that the actual cost to the insurance industry would only be revealed when the scheme was in operation.
"With the system for road accident payouts, the take-up by the NHS was very low because the costs and the bureaucracy of that implementing that scheme was too high."
Geraint Day, head of health and environment at the Institute of Directors said: "This measure is highly likely to have an effect on insurance costs, which are already of concern to many businesses."
He added: "We reject any implication by the Department of Health that employers in general are failing to take adequate steps to prevent accidents at work."
But TUC General Secretary Brendan Barber said: "It is only right that where employers cut corners at work and take risks with the health and safety of their employees, it is them, not taxpayers, who pay the cost of treating the hospitalised ill or injured worker.
"Employers can easily protect themselves from increased costs by ensuring that employees do not get injured through negligence in the workplace."