Boots has paused any new bookings for private flu vaccinations at its shops in Northern Ireland, the pharmacy chain has confirmed.
The chemist has stopped taking any new bookings for flu vaccinations for its NHS under 65s service and private service in England due to an increase in demand.
However, in Northern Ireland NHS flu vaccinations are done through GPs, so it is only the private service which Boots provides to customers in NI which will be affected by the move.
It comes shortly after people were advised to get flu jabs to help protect against the "double danger" of flu and coronavirus.
Having flu and Covid-19 together significantly increases your risk of death, government scientists have said.
A Boots UK spokesperson said: “We know that this year, our customers have been more conscious than ever about protecting the health of themselves and their families, and protecting against flu has been front of mind for many of us.
“As a result, we have seen more people than ever booking early to get their flu vaccinations.
"We have been closely monitoring our stock levels, and made the decision this weekend to pause taking new bookings for our private under 65s Flu Vaccination Service. This is to make sure we can vaccinate the patients who have already booked their appointments with us.”
Boots increased its order for flu vaccinations by 20% this year, but said levels of demand have been "unprecedented" as a result of the pandemic.
Dr David Irwin, consultant of public health at the Public Health Agency, told BBC Radio Ulster's Nolan Show that flu vaccinations for people over 65 and those under 65 in an at risk group are covered exclusively through the GP system in Northern Ireland.
"For anybody who normally should have their vaccine because they are over 65, or because they are in an at risk group under that age, they still will be able to get their vaccination through their GP," he said.
Dr Irwin, who is heading up the flu vaccination programme in NI, said there is enough flu vaccine for people over 65 and those in at risk group in Northern Ireland, but it is not clear if there is enough vaccine for everyone in NI who wants it.
Dr Irwin said the flu vaccination programme is due to start in Northern Ireland on October 1.