After a period of very low case rates during the summer, 10 new cases were confirmed in North Somerset on Sunday - the first time the daily number of cases has reached double figures in three months.
The council's Director of Public Health, Matt Lenny, said: "Today we have seen the number of cases in North Somerset reach 20.5 per 100,000 population - the highest rate in the South West. This is slightly above the national average rate of 16 per 100,000 people. We want to slow and reverse that rise as quickly as possible.
"Our relatively low population base means our rate can rise rapidly based on a smaller number of cases but clearly the relative increase is still important and something we want to manage as proactively as possible.
"It's down to every single resident to do their bit to prevent the spread of infection. There is no room for complacency, and regardless of age, or state of health, everyone must play their part. This includes frequent hand washing for at least 20 seconds, maintaining social distancing of two metres wherever possible and self-isolating and booking a test if they experience any of the symptoms of the virus.
"These really are the most effective ways we can reduce the impact of the virus on our community. The recent rise in case numbers should act as a wake-up call for everyone that the virus is still present locally."
Cllr Don Davies, Leader of North Somerset Council, said: "We all have a duty to take responsibility for our own actions in minimising risk of spread and to follow the latest national guidance around testing and self-isolation.
"If people are returning from holidays in countries with quarantine measures in place they must self-isolate for 14 days without exception.
"If people have symptoms or live with someone who has symptoms they must self-isolate and follow the advice at www.nhs.uk/coronavirus.
"No-one is immune, and while you might think you're not at risk, the simple fact is that none of us truly knows the devastating impact the virus can have on us or our loved ones until it's too late, especially those who are vulnerable or a little older.
"Other parts of the country have seen lockdown measures imposed where case numbers have risen, and while we're not in that territory yet, we could be if we don't all do our bit to protect ourselves and our friends and family. Anyone can get it. Anyone can spread it."