TORONTO — A shortage of school bus drivers has been cited as the cause of service delays for students of two school districts here.

The Toronto Catholic District School Board and Toronto District School Board have issued alerts about the school bus delays this week.

According to the districts, students who use Attridge Transportation, Wheelchair Accessible Transit Inc., or Sharp Bus Lines Ltd. “should expect significant delays and the possibility that some buses may not be running due to an unanticipated bus driver shortage.”

“Schools will make every effort to contact affected parents/guardians directly,” a statement from the districts said. “Students will remain at school under the supervision of staff until they are picked up.”

The Toronto Student Transportation Group lists current delays for various school bus routes. At press time, some showed delays of an hour or more.

“We are working to fix this issue as soon as possible,” the districts said in the statement.