Auckland District Health Board has discovered more people were mistakenly left off waiting lists - adding to a group that includes children as young as six.
Some patients were assessed as needing surgery as far back as 2015, but were missed from waiting lists until the problem was discovered in April.
A gynaecology patient had her specialist appointment in February 2015 - more than three years before the error was discovered.
The DHB carried out urgent work to clinically assess the patients and said none came to harm because of the delays.
The Herald revealed the error in July, which was discovered only after one called to ask when their surgery would be.
At the time, the DHB said it could not say what surgeries patients were waiting for, but it has now released that and other information under the Official Information Act.
That details further analysis that found another four patients were affected, bringing the total to 47. Most cases were in 2017, but 12 had specialist appointments in 2016, and two in 2015.
Patients were waiting for eye procedures (18), and others for general surgery (nine), orthopaedics (nine), ear, nose and throat (five), paediatric orthopaedics (three) and gynaecology (two).
Ages ranged from six to 89.
One of the patients affected told the Herald he had since received an apology.
His GP referred him to a specialist, and they determined he needed to have a suspected basal cell carcinoma - the most common but least dangerous type of skin cancer - removed. He was weighed and had his blood pressure taken.
"They said, 'We will be in contact really soon'. Then I never heard from them for a year, and then they suddenly rang me back and said, 'Can you come in for an operation on Tuesday'. I was booked in within a week."
"The consultant at Greenlane said, 'We don't know what happened, it got lost'. It's a bit weird. It would be a worry if I had a melanoma or something, because if you leave that for a year that can go really bad.
"It's more annoying than anything because I just thought it was a long waiting list. But apparently not."
The man, who asked not to be named, said after the procedure in early June it was discovered what had been removed was actually a rare tumour of the hair follicles. They decided to remove more, and he had another operation on July 10.
In releasing the new information, the DHB said it had reviewed 75,000 patient records to identify the group of 47 who were left off waiting lists. An independent report had also been commissioned to work out what went wrong and how to guard against future problems.
Recommendations include running a new reconciliation report to make sure all patients seen in clinic are added to lists within 24 hours, and to appoint a waiting list manager.
An automatic report is run as a back-up to identify any patients mistakenly left off waiting lists, but failed to do so in the 47 cases.
Patients mistakenly left off surgical waiting lists at ADHB include:
• 18 ophthalmology patients
• 9 general surgery patients
• 9 orthopaedics patients
• 5 ear, nose and throat patients
• 3 paediatric orthopaedics patients
• 2 gynaecology patients