NHS Grampian’s waiting times are the joint second-worst in Scotland, with nearly one-in-four patients failing to be seen within the 18-week target time.
Latest figures from the Scottish Government show 77.4% of NHS Grampian patients were seen within the target time.
North-east MSP Mike Rumbles, Lib Dem, said the figures showed performance was unacceptable.
He said: “Quite frankly these figures are outrageous.
“In the past six months around a quarter of patients in the North-east have missed their 18-week target and the SNP Government should hold their heads in shame.
“Performance throughout Scotland is at an all-time low and NHS Grampian is well below even those abysmal standards, which is simply unacceptable.”
The Scottish average for NHS boards at the last count was 83.8% and the Scottish Government’s target time is for 90% of patients to be seen within 18 weeks.
Highland Council also saw 77.4% of patients within the target time, with only Ayrshire and Arran worse at 72.1%.
However, NHS Grampian’s latest statistics are the best for six months, with numbers trending downwards since an 80.4% high point in June.
An NHS Grampian spokesman said: “We endeavour to meet the 18-week referral to treatment standard for specialist care.
“Our overriding priority is to provide a high-quality service for patients whether admitted for a planned procedure or in an emergency.
“Our waiting time targets are challenging, but we would like to assure people this situation is constantly monitored and appropriate treatment is offered urgently where required.”
Health Secretary Shona Robison, SNP, pictured, said NHS Grampian received £918,000 of a £10m pot to cut waits in the coming months.
She said: “It’s extremely important to us that patients who are waiting for treatment such as surgery, a diagnostic test or an outpatient consultation, are seen as quickly as possible.
“We’re investing substantially in social care and community care, with a view to keeping people healthy at home for as long as possible.
“These changes won’t happen overnight but they are part of a clear, long-term strategy of matching increased investment in our NHS with reform to ensure our health service is providing care to the people of Scotland long into the future.”