Two new Covid-19 test centres will be opening in Cardiff due to a sharp rise in cases across the city.
Cardiff Council said the new test centres will create 2,000 new testing slots per week - with one opening in Ely on December 16, and another in Cardiff Bay on December 17.
A spokesman said: "The Welsh capital has seen infection rates grow by 90% over the past week to reach the highest levels yet in the city, and with the positivity rate at 18% it’s clear the virus is spreading through the community making it extremely difficult to contain."
Cardiff Council leader Huw Thomas said: "We are at a stage now where the rise in numbers is stark. If we don’t follow the rules our NHS and our services could be overrun by Christmas The current predictions are dire."
He added that there have been nearly 16,000 confirmed cases of the virus within Cardiff and the Vale, with 11 people currently being treated for it in intensive care units.
He also said that 278 of the health board's medical staff are currently unable to work as they are self-isolating.
“Hospital resources are being stretched and staff pushed to the limit following their experience at the sharp end of the pandemic," he said.
He added that a large number of police officers are currently self-isolating after contracting the virus on shifts that "regularly involve breaking up illegal gatherings."
Cardiff has a rate of 451.6 positive coronavirus cases per 100,000 inhabitants, as of December 15.
The rate across Wales is 416.5 per 100,000.
On Tuesday evening, Cardiff and Vale University Health Board confirmed that staff at a mass vaccination centre in had tested positive for coronavirus.
The health board said it is continuing to test other staff members, but the number of workers and how many people could be made to self-isolate has not yet been revealed.
