Canada's chief public health doctor says a slow but steady increase in the number of people testing positive for COVID-19 is a cause for concern.

Dr. Theresa Tam says today the average daily number of people testing positive over the last week is 545 — a 25 per cent increase over the previous week which saw a daily average of 435, and 390 a week before that.

That number increased every day over the last week prompting Tam to remind Canadians not to get complacent about their risk of contracting the novel coronavirus. Overall, in the last week, 3,955 people tested positive across Canada, and 28 people died of COVID-19.

That compares to 3,044 positive tests and 44 deaths in the week prior.

Tam says most Canadians are following public health advice and that has allowed Canada to keep the COVID-19 pandemic "under manageable control" but says she is concerned about the uptick in positive cases.

"This is a concern and a reminder that we all need to maintain public health measures to keep COVID-19 on the slow-burn path that we need," she said in a statement.

"As we enter the fall, Canadians will need to be even more vigilant about following public health guidance, particularly as the cold weather shifts activities indoors."