Latest figures show there were 18 new cases per 100,000 residents in the city last week, which has increased from 8 the previous week.
For comparison the rate of new cases in England week ending 3 July was 6 new cases per 100,000 residents.
The county council has stressed that the rate is still significantly below that which prompted local lockdown measures in Leicester.
Claire King, Consultant in Public Health at Cumbria County Council, said: “After a steady overall decline, the rate of infection in the Carlisle area has gone up over the past week. The increase is not large, but it is concerning and we cannot ignore this.
“This is a powerful warning that people must not be complacent and the fight against COVID-19 is not over. Social distancing, hand washing, getting tested if you have symptoms, self-isolating if necessary and wearing face coverings or masks when required are absolutely crucial."
She continued: “We are monitoring the situation very closely, working with colleagues in the NHS and other local partners. At the current time, we are a very long way from re-imposing lock down restrictions given the overall low number of cases. But we have to recognise how easily COVID-19 can spread and that if we see these numbers continuing to increase then restrictions may become necessary.
“We will be analysing the data further over the next few days to learn more and if we need to adjust our action, we will do so."
Cllr Deborah Earl, Cabinet Member for Public Health and Communities, said: “People in Carlisle have done a great job so far and I know it hasn’t always been easy to stick to the rules. We’ve always said that it was when the lock down restrictions ease that we’ll have to be at our most vigilant and these figures underline that.
"I urge people to do their bit to help keep their family, friends and local communities safe. Follow the rules and we can avoid having to take further action.”
The key actions for the public to take now are:
Maintain social distancing in line with current advice
Wash hands regularly
If you have symptoms, get tested and self-isolate until you know the outcome
Follow the advice of Contact Tracers if they get in touch
Wear a face covering or mask where required
The symptoms of coronavirus are:
a high temperature,
a new, continuous cough,
a loss or change to your sense of smell or taste
Where can I get tested for coronavirus in Carlisle?
Local testing is available in Carlisle at mobile testing units at Brunton Park on the following dates:
Tests must be booked through national website.
A swab test can also be booked at the Penrith drive-through test centre via this website.
More information on the situation in Carlisle can be found here.