Managers at NHS Grampian have been told to cut £20m from their budget, BBC Scotland has learned.
An overspend at Aberdeen Royal Infirmary is being investigated
Confidential papers seen by the BBC also reveal that an investigation is under way into a "large overspend" on drugs in an Aberdeen cancer unit.
The £212,000 overspend relates to the Anchor unit at Aberdeen Royal Infirmary.
The board's finances are due to be discussed at a meeting of health officials on Friday.
NHS Grampian has an outstanding debt of just under £11m. It hopes to reduce that to £8m by next April.
At the meeting, senior managers will discuss how the savings can be achieved.
The confidential report, covering April and May of this year, said the Anchor unit's overspend was "anticipated" but that the level was "surprising".
Allan Gall, finance director at NHS Grampian, said of the findings: "NHS Grampian expects its total funding to March 31 2006 to be in the region of £750m.
"This is a best estimate at this stage in the financial year as funding flows will emerge and change as the year progresses.
"The expenditure budget-setting process which began in December 2004 has produced a projected expenditure total for the year to March 31 2006 of around £770m.
"Thus, if NHS Grampian progressed its plans based on this draft scenario, it would lead to an overspend of £20m.
"The reference to an investigation into a budget overspend in the first two months of the financial year is that budget managers have been asked to confirm that the larger than normal level of expenditure will be smoothed out during the remainder of the year."
Scottish National Party health spokeswoman Shona Robison insisted that patient care must not suffer because of the financial difficulties.
Ms Robison said: "The Scottish Executive has claimed that there are higher levels of investment in the NHS.
"However, we continue to see health boards such as NHS Grampian and Argyle & Clyde in financial difficulty.
"We must ensure that the executive fully funds decisions made centrally such as pay awards and that local health boards and patients do not have to continue to shoulder the financial burden of (Health Minister) Andy Kerr's decisions."