NHS Tayside has apologised to those who had to wait in long queues outside the vaccine clinic in Dundee this week.
It comes after the health board opened up drop-in clinics to those aged 18-29 to get vaccinated without need for an appointment.
Separate queues were put in place for those with booked appointments and walk-ins.
Despite this, those with appointments for their first or second dose had to wait for almost two hours after their scheduled time to receive their vaccination.
People with appointments stuck in the queues at Caird Hall yesterday took to social media to complain about the waiting times.
Kate Clark commented: “Complete joke.
“[I] had a 4.30 appointment and got taken after 6. Pointless sending appointments out.”
Joyce McRither said: “People with appointments still had to wait in a huge long queue for over an hour.
“What’s the point in sending out appointment times?
“My hubby told them he wasn’t standing in it and had to schedule his work around his appointment time.
“Waste of a parking ticket.”
The problems were made worse when it began to rain later in the afternoon, leaving those outside the Caird Hall soaked.
Kelly Barton said: “Had to stand in rain for hour and a half.
“Appointment was at 3.20 (arrived at 3pm), got it at 4.45, others with no appointment was able to just walk straight in.
“Shocking, what’s the point in giving appointments if we need to wait until the ones without them are seen first?”
The health board said they have evaluated the queue system and have now increased the number of people giving vaccinations at the clinics to reduce waiting times.
A spokesperson for NHS Tayside said: “Yesterday was the first day of the 18 to 29-year- old drop-ins which saw a welcome increase in the number of people attending for vaccination.
“There is a separate queue for those with appointments, but due to the huge demand yesterday, some people experienced a longer wait at the Caird Hall and we would like to apologise for that.
“We have reviewed the queue management system and have increased the number of vaccinators and support staff in place.
“We would like to thank everyone for attending so far and would strongly encourage others to come along for their vaccine.”