A third of NHS organisations in the South East responsible for looking after healthcare have been rated inadequate.
Five out of 14 Clinical Commissioning Groups (CCG) across Kent, Sussex and Surrey are now in special measures.
CCGs plan, buy and monitor healthcare in their regions and NHS England said some were failing to provide good value for patients.
The groups said measures to regain financial control were under way.
The groups rated inadequate are: Crawley, Coastal West Sussex, Horsham and Mid Sussex, Dartford, Gravesham and Swanley, East Surrey.
Speaking to BBC South East's health correspondent Mark Norman, the CCGs all said they had already begun to address the issues raised, and were looking forward to the additional support they had been offered by NHS England.
Geraldine Hoban, accountable officer at NHS Horsham and Mid Sussex CCG, said: "We're looking at savings of about £16m this year.
"We will look to do that by commissioning different sorts of models of care for patients so we absolutely are committed to this not affecting the quality of services people receive or their access to services they need."
Dr Laura Hill, acting clinical accountable officer at NHS Crawley CCG, said: "Crawley CCG is facing significant pressures, which have continued as the demand for health and care has increased and people live with more complex conditions for longer.
"A great deal of work is already under way within the CCG to improve our position, including our Financial Recovery Plan; a robust and ambitious strategy to address our financial situation.
"This latest rating shows the need to transform local health and care services, to reflect the needs of our patients."
Patricia Davies, accountable officer for Dartford, Gravesham and Swanley CCG said the rating was "no surprise, given the weight of the financial challenges in previous years".
"Funding levels have not kept up with unprecedented growth in the area, and this has been further impacted by the wider trend of rising demand for health services.
"We recognise there is much to do with our partners in health to improve and to reduce the deficit in the coming months, and that there will be some difficult decisions ahead... it is important to state that the rating is in no way a reflection of the hardworking and committed staff in the organisation or of those in our partner organisations," she said.
Together, the five groups control a budget of £1.2bn and provide healthcare to 1.3 million patients.
Nationally, CCGs control two thirds of the total NHS Budget.