Police will have the power to break up house parties with more than 15 people starting Friday in a bid to reduce transmission of Covid-19.
Health officials have warned that such gatherings could present “high-risk super-spreader environments.”
Premier Nicola Sturgeon said the move was needed in anticipation of an increase in gatherings indoors as winter approaches.
And she said acting now could prevent tougher lockdown measures.
The measures were first announced last week and the new limit was confirmed on Thursday.
Under current guidelines, no more than eight people belonging to a maximum of three different households should meet inside.
The new law takes into account the varying size and composition of families and sets the limit for an indoor party at 15 people if more than one household is present.
During her daily press briefing, Ms Sturgeon said: ‘We know from reports from our testing and protection teams – and also from evidence around the world – that these types of gatherings pose a significant risk of transmission. . ”
She acknowledged that colder weather would increase the likelihood of large social gatherings indoors, but said the new legislation was “not a green light” to ignore existing guidelines.
Ms Sturgeon added: “Recognizing that we intend these new legal powers to be only a last resort and to be used in the most egregious violations of guidelines, we have decided to set a higher threshold for their use.
“Ensuring that the police have the power to disperse large house parties where necessary is another important tool in trying to keep this virus removed. ”
She added that it would help reduce the potential for future clusters and outbreaks and prevent greater lockdown restrictions.
Speaking to young people, Ms Sturgeon stressed that this decision was “not to prevent people from having fun” and added: “We are not trying to control your social life”.
But the prime minister said the move was necessary for “the health and general well-being of the country.”