Two areas of "significant concern" were radiology, accessing MRIs, and radiation oncology - both services impacting patients with multiple tumours.
The report said this strain was a result of seasonal capacity rather than ongoing issues within services. But lung services continued to be impacted adversely.
An Auckland DHB spokesperson said it was a matter they were taking extremely seriously.
"We are gearing up so our hospital services are match-fit for an extremely busy winter."
This surge comes at a time when Middlemore Hospital is also bursting at the seams.
A letter from health bosses at Middlemore Hospital to Health Minister David Clark revealed shocking fears including cancers being discovered too late and poorer patients being overlooked.
On behalf of department heads, the Counties Manukau DHB director of medicine wrote that the general medicine department was in crisis, with fears that the hospital wouldn't cope with a surge in flu cases.
The four DHBs that make up the northern region – Northland, Waitemata, Auckland and Counties Manukau – have made a case for a new hospital in their Northern Region Long Term Investment Plan.
Health Minister David Clark said last month that the Government was aware of the pressures on Auckland hospital services that come with a growing and ageing population.
"But that does not necessarily require a new hospital.
"Over time we will increase hospital capacity in Auckland, that's one reason why the Government pumped $750 million into capital investment in health in the Budget," he said.
In May, Auckland Hospital opened a new unit in a bid to reduce these numbers.
The ADHB spokesperson said the Clinical Decision Unit was designed to reduce the number of patients in ED, improve the flow of patients through the hospital and reduce unnecessary hospital admissions.
"It would also improve patient safety and the experience for our patients and their families."
Wait times for May are yet to be released.
