Over 250 people residing in Greater Manchester are not responding to quarantine requests, say police.
Since July 22, officers from Greater Manchester say UK Border Force have alerted them to 263 individuals who have returned to the UK after international travel who are not self-isolating.
Right now, there is an ever-changing list of countries and territories considered safe holiday destinations for Britons.
Dozens of destinations are on the list - meaning returnees from there are exempt from 14-day quarantine rules - but countries can be "rapidly" removed from the list without warning.
Those that are required to self-isolate may be contacted by Public Health England to check they are following the regulations. If there is no response after a number of attempts of trying to make contact, the details of the individual will be referred to the police by UK Border Force.
GMP say once a case has been referred to them, officers will visit the address of the individual and attempt to engage with the individual and encourage them to follow the rules and in the last resort enforce action.
If someone breaches self-isolation they could be handed a £1,000 fixed penalty notice in England or face potential prosecution, the Home Secretary Priti Patel said.
To date, Greater Manchester Police have issued two fixed penalty notices and visited all 263 individuals who are reported to have breached the self-isolation regulations.
Superintendent Andrew Sidebotham, said: "It's really important for people to self-isolate for the full 14 days when coming back to the UK as it can take this length of time for symptoms of COVID-19 to develop. During this time you could unknowingly pass the virus on to others, even if you don't have symptoms.
"When contacted by Border Force please respond as once a case is referred to police, it takes up a number of resources in order to visit the address and make contact with the individual. As well as this officers are putting their health at risk by visiting someone who could potentially be carrying the virus. A risk that is preventable if everyone self-isolates as required."