Extra vaccinators were scrambled to Caird Hall on Monday, as wintry weather led to a bottleneck of pensioners waiting for their jabs.
Health chiefs have apologised and said they will review arrangements for the Dundee city centre venue, after hundreds were left queuing in the snow for about an hour.
At one point, the queue of people snaked around the square to Crichton Street.
Heavy snowfall and icy conditions meant that some people were late for their appointments, while others turned up too early, officials said.
The weather was also blamed for a shortage of staff.
Caird Hall opened last week to administer vaccines to people aged between 65 to 69, as well as some in the 70-79 age group.
A spokeswoman for NHS Tayside said: “We are aware that some patients experienced a longer wait today at the Caird Hall for their vaccination appointment and we would like to thank them for their patience and apologise for their wait.”
She said: “Due to the adverse weather conditions, the queue was longer than expected due to a combination of factors.
“Some patients arrived late for their appointments and some patients arrived early, which meant more people than planned attended at the same time.
“The weather also meant that some staff were not able to get to the site as planned. Due to the need to maintain 2 metres distance between people, there is a limited capacity to hold people inside the venue.”
The spokeswoman added: “In response, more vaccinators were brought in to increase the number of people who could be vaccinated and reduce the number of people waiting. We are also reviewing our plans to identify any improvements that can be made.
“We would ask people where possible not to arrive more than five minutes before their appointment time to help ease congestion.”