Police say they will deal with motorists 'robustly' if they are caught driving on closed roads.
Officers say they have received numerous complaints - particularly about drivers using the Tholt y Will Road and Peveril Road in Peel.
Peveril Road was closed last week after the road collapsed.
The Department of Infrastructure says it was due to a void forming along the line of the sewer which was made worse by the recent wet weather.
Repair work started yesterday - a diversion is in place while the work is carried out.
Framework of new Sea Services Agreement ready, says minister
Attorney General says he's stepping down
Road closures in two towns for running event this week
Six weekend ferry crossings could face disruption
President of Tynwald announces retirement
Police close Mountain road
Fuel firm says "fingers crossed" for calmer energy costs
Ring doorbells will need data protection registration - but shouldn't cost you money