Patients waiting at Dunedin Hospital's crowded eye clinic regularly have sit on the floor, despite the hospital saying it only happened once, the union for hospital workers says.
The Southern District Health Board has been trying to clear a waiting list of thousands of delayed ophthamology appointments that has built up over the last year.
At least 14 patients suffered moderate or major loss of vision late last year while waiting for follow-up eye appointments.
Public Service Association spokeswoman Julie Morton said the DHB's haste to clear the backlog had seen patients, some of whom were elderly, forced to sit on the floor in a crowded waiting room.
"There's not enough places to sit down," she said.
"My issue with that is it's just not appropriate to put patients on the ground and secondly it's a health and safety matter."
The DHB's chief medical officer Nigel Millar said patients had to sit on the floor on one occasion last month when the DHB ran an extra clinic and saw 140 patients in one day after securing a locum at short notice.
"We acknowledge the clinic on June 6 was very busy, and the waiting room became very crowded. This was not ideal and apologise to any patients who were inconvenienced by this."
But Ms Morton argued the situation was not a one-off.
"This is happening all the time," she said.
"Every time I've been in there myself, all the chairs are full and there's people sitting on the floor."
She said clinic staff themselves were under huge pressure dealing with the numbers of patients, some of whom were unhappy at the long wait times.
One union member had told her a patient waited for seven hours before giving up and leaving.
Staff had been working overtime to organise the extra clinic days, she said.
Dr Millar said about 15 locum clinics had been held this year, and all except the one last month involved reasonable lead-in times.
He said extra seating had been ordered, but did not arrive on time for last month's clinic.
"It was unfortunate the additional seating that had been ordered did not arrive in time for this clinic, and again apologise for any discomfort this caused."
DHB chief executive Chris Fleming said the extra seating meant the waiting room could now seat 56 people.
He said the clinic saw between 64 and 189 patients every day, with an average of 124.
Mr Fleming said the DHB was not aware of patients sitting on the floor until the PSA reported it, and he was unable to confirm it had only happened on one occasion.
Additional staff had been employed to ensure permanent staff were not unfairly overworked, he said.
"There is an increased number of patients coming through the eye department, and there will be some days busier than others."
The DHB was unable to provide a response on how many patients were still on its waiting list for delayed appointments.