NHS Grampian has expressed concern at rising Covid cases and the dominance of the Delta variant.
The "highly infectious" strain is now said to be accounting for 80% of cases throughout the area.
The health board said that at the end of May numbers were eight or nine a day but cases were now three times that.
Dr Derek Cox, consultant in public health, said: "We need to take action now, before we catch up with other parts of the country."
The Delta variant, which was first identified in India, is now the dominant variant in the UK.
Dr Cox said the situation was concerning for a number of reasons, including that the variant was more than 60% more infectious than the Alpha variant, and appeared to be more resistant to vaccines.
"I know there will be those who will point to the very low numbers of people currently in hospital and say we are making an undue fuss", he said.
"The simple fact is, the third wave is here, but we have a window of opportunity to slow its progress across Grampian and give as many people as possible the opportunity to get both doses of Covid-19 vaccine."
'Make a real difference'
NHS Grampian said it would make testing "as available as possible".
A Covid outbreak in Moray was recently brought under control.
Dr Cox said: "Our experience in Moray has shown that if we work hand-in-hand with the community, then we can make a real difference."
He urged against unnecessary travel outwith people's own area, and avoiding crowded indoor places.
"Our choices right now will determine how quickly we can progress towards something approaching a normal life once again", he said.