Residents in Perth and Kinross will effectively find themselves back in full lockdown on Boxing Day.
First Minister Nicola Sturgeon confirmed the return of the "stay at home" message on Tuesday.
She also refused to rule out bringing a travel ban between local authorities into law.
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At her latest coronavirus update to parliament, Ms Sturgeon also said garden centres and DIY stores would be forced to close.
The first minister announced on Saturday that the entire Scottish mainland would go into level four of restrictions in an attempt to stop a new strain of COVID-19.
But on Tuesday she told parliament the new strain is more prevalent than first thought in Scotland.
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It comes as the infection rate in Perth and Kinross rose by nearly 45 per cent in a week.
The current seven-day rate of infection is 147.7 up to December 19 - a rise from 102 the week before.
There were 224 cases compared with 155 the week before, while the percentage of positive tests has risen above the five per cent mark and now sits at 6.1 per cent.
