Four health boards which are due to see their overall budget deficits triple in size will not be bailed out, the Welsh Government has said.
The boards are forecast to over spend by £151m this year.
In one case – Abertawe Bro Morgannwg University Health Board (ABMU) – the financial outlook is said to be “extremely challenging” with a deficit of £53m.
The health board said it was attempting to cut agency staff costs.
As well as ABMU, which covers Swansea and Bridgend, there are overspends at Betsi Cadwaladr in north Wales, the Cardiff and Vale board and Hywel Dda in mid and west Wales.
Betsi Cadwaladr’s deficit is now forecast to be £30m, Hywel Dda £51m, ABMU £39m and Cardiff and Vale £31m for the financial year 2016-17.
In the previous year, Betsi Cadwaladr and Hywel Dda had a combined deficit of £50m while Cardiff and Vale and ABMU both broke even.
Betsi Cadwaladr has been under direct control of the Welsh Government since June 2015.
The other three boards were placed under an increased level of scrutiny from ministers in September last year due to doubts about their ability to tackle the financial challenges they face.
‘Overall budget will balance’
A Welsh Government spokeswoman said: “The position in these four health boards is unacceptable, and we have made it clear that we expect them to take action to significantly improve their financial position.”
She said ministers will not approve financial plans “that do not deliver such improvements”.
“Individual organisations who exceed their allocated resources, have not – and will not – be bailed out,” she said, adding that the government is “working alongside all organisations to improve their respective positions” and that the “overall health budget will be balanced for the 2016-17 financial year”.
ABMU has gone from a break-even position to a forecast deficit of £39m this year, and another forecast deficit of £53m next year.
The health board has average running costs of £3m a day, so a £39m deficit is equivalent to the cost of running the board for 13 days.
It said it was focusing on an intensive recruitment drive to cut down on the cost of agency staff, as well as reducing waste in prescription medication.
A spokeswoman said: “There are many challenges facing us when trying to identify savings that won’t compromise patient safety and quality of care, at the same time as demand on our services increases.
“We are aware there is no additional funding available at the end of this year over and above what we’ve already received, as we are working with all our staff to ensure they are able to contribute to our short and long-term saving plans.”
Analysis by BBC Wales political editor Nick Servini
These figures show a dramatic deterioration in the finances of four out of Wales’ seven health boards.
They have also prompted a hard-hitting response from the Welsh Government which, until this point, has been keen to stress how they approach problems together.
The tone resembles the approach of the man in charge of the English NHS, Jeremy Hunt, who has not been afraid of calling out heath trusts he believes are under-performing.
The Welsh Government has called for a significant improvement in the financial performance.
That will be easier said than done in the face of intense pressure on these organisations.