Police in Rochdale are receiving an 'increasing number of calls' about families and children not isolating after being sent home from school.
Parents have been warned to follow the rules, or face a hefty fine.
In a letter to parents Gail Hopper, director of children's services in Rochdale, asked families to 'work with us to reduce the number of infections'.
Ms Hopper wrote: "I am writing to you after discussions with Greater Manchester Police in Rochdale borough who have received an an increasing number of calls about children and families who are not following the requirement to isolate after being sent home from school and told to do so.
"The purpose of this letter is to ensure you understand what is expected and what could happen if you do not comply."
The letter goes on to warn: "Breach of self-isolation could lead to a substantial fine because of the risks to other members of the community.
"The risk is greater currently as infections are rising. It's important that you know that any reports of children and families not isolating when told they must are being shared with Greater Manchester Police who are following up with home visits."
There were 584 new covid cases in Rochdale in the week ending June 21 - up 18 per cent, week-on-week
The borough's infection rate is currently 262.6 cases per 100,000 people, more than double the average across England.
On Thursday the Manchester Evening News reported how at least 150 schools across the region had been hit by covid closures.
At his weekly press conference on Wednesday Mayor Andy Burnham said 2,000 children were isolating in Manchester and 3,000 in Oldham, adding the situation is similar across the region.
With the number of bubble closures still rising across the region, it's becoming 'almost impossible for headteachers and teachers to manage' and causing a huge problem for parents who keep needing to take time off work, Manchester council leader Sir Richard Lesses said at the same press conference..
"Headteachers are feeling under phenomenal pressure and are crying out for help," said Sir Richard.
