NHS Highland said it “very much regrets” that 486 operations were postponed due to a dust contamination and cracks in some theatre walls.
Problems started late last month when it was revealed that theatres had first been contaminated due to building work requiring a deep clean operation to make them safe.
Then two weeks later “superficial” cracks in the walls were revealed which had to be repaired before operations could take place, leading to more delays.
Emergency operations were still performed throughout the recent disruptions in the theatres.
But most elective surgery was rescheduled or moved to other hospitals in Caithness, Lochaber and Sutherland.
Edward Mountain MSP, who raised the issue of postponed operations at First Minister’s Questions, said: “I find the whole thing completely unacceptable.
“With nearly 500 operations missed, which is considerably more than was originally estimated, there will be a lot angry and disappointed patients in the Highlands.
“I want to know the total of operations postponed because of the IT problems, sickness, dust and the walls.”
A spokesman for NHS Highland said: “In terms of getting up to full theatre capacity, significant work has been happening round the clock.”
That work was completed on Wednesday and “a cleaning plan is now in place and will be followed by air sampling testing” with a view to reopening the theatres for Monday.
The spokesman said: “We very much regret that 486 elective procedures had to be postponed.
“We would hope, given the extremely difficult circumstances that the public understand why it was necessary to ensure we operated in a safe and appropriate environment.”
Despite the planned reopening some patients may still have a long wait on their hands as clinical teams comb through records “to prioritise those with greatest clinical need”.
“Next week we will be in a better position to assess the delays for each patients and how we will communicate with individual patients.”
In less than a month starting from January 9 hundreds of operations were cancelled due to a flu outbreak, the dust contamination, and cracked walls.
Last October dozens more operations being cancelled when a flood in the basement led to IT servers being knocked out of action.