A total of 324 operations have been postponed at hospitals across Glasgow since Friday following the forced closure of a decontamination unit.
NHS Greater Glasgow and Clyde said cancelling scheduled surgery would allow staff to concentrate on emergency, trauma and urgent cases.
Remedial work is being carried out at the Cowlairs unit in Springburn.
The unit, which supplies operating theatres with surgical equipment, failed a safety inspection last week.
The health board confirmed 138 operations were cancelled on Wednesday, while 87 were postponed on Tuesday.
These included a "small number" of urgent cases which require specialised instruments.
A total of 46 operations were postponed at six hospitals across the city on Monday and 53 the previous Friday.
The health board said it regretted the inconvenience caused to patients and will write to the those affected to reassure them they will be admitted shortly.
Cowlairs is responsible for the cleaning and sterilising millions of instruments a year which have to be collected, decontaminated, sterilised, tested, repackaged and returned to clinical staff quickly to ensure thousands of patients can be treated each day.
The health board said the closure of the unit on Friday created significant challenges.
It has another centre at Inverclyde Royal which is providing some short-term cover for the Glasgow area while other health boards are also providing assistance.
A spokeswoman said: "Our staff have been working tirelessly to resolve the current situation and to put in place alternative arrangements for the sterilising of all the equipment necessary to support the hundreds of operations that take place each day.
"The logistics of this have been challenging; we are working with other health boards over the country to create the capacity needed to meet the demand.
"Whilst we have been able to continue to turn around many thousands of instruments over the past few days, we have had to restrict our programme of planned surgery to enable us to prioritise emergency, trauma and urgent cases."
She said some, but not all, non-urgent cases have been rescheduled.
The spokeswoman added: "We have also had to postpone a small number of urgent cases involving highly specialised instruments and are arranging for these patients to be seen as a priority.
"We are sorry for any inconvenience caused and would wish to reassure patients that we are working round the clock to bring the unit back into operation as quickly as possible."