TORONTO -- Ontario teachers and other school board employees have been taking more sick days since they stopped being able to bank that time, the province's auditor reported Wednesday.

In her annual report, Bonnie Lysyk said a study of more than 50 school boards found that in the last five years, sick days increased by about 30 per cent -- from nine days in the 2011-2012 school year to 11.6 in 2015-2016.

The beginning of that five-year period is when the province stopped letting teachers bank sick days. Before that, teachers were allowed 20 paid sick days a year and could carry them forward, getting paid out upon retirement for up to 200 unused days.

Now, all school board employees get 11 fully paid days, plus 120 days paid at 90 per cent, Lysyk said. Several trustee associations told the auditor that 90 per cent pay is not a penalty.

"Some trustee associations told us that since education-sector workers lost the ability to bank sick days, they were more likely to use the sick leave that they would no longer be able to bank," the auditor's report said.

The auditor team visited four school boards as part of its audit and all of them said the changes in the sick leave plan contributed to the increases.

"I think when you hear the term sick leave and sick days you assume that people are sick," Lysyk said. "We're commenting that school boards perhaps need to put in place some sick leave policies."

Custodians and maintenance employees had the highest average sick days in the 2015-2016 school year, at more than 16 days. Educational assistants and early childhood educators had the largest increases, at 41 per cent and 37 per cent. That amounted to 16 days and about 13.5 days, respectively.

Elementary teachers took an average of more than 11 days and secondary school teachers took and average of almost 10 days, the study found.

Some boards said that custodial and maintenance workers take more sick days because of the physical nature of their jobs and education assistants are more susceptible to getting sick because of close contact with students, the auditor's report said.

Harvey Bischof, president of the Ontario Secondary School Teachers' Federation, said he sees no reason to draw a connection between the end of banked sick days and the five-year increase.

"I know that our members are reporting among other things, increased incidents of violence in the workplace to which they are subject, resulting in physical injury, resulting in mental stress," he said.

The union approached one school board employer organization to suggest pilot projects that would intervene early when employees are off sick to provide them with supports so they can return to work, Bischof said.

The Elementary Teachers' Federation of Ontario and the Canadian Union of Public Employees, which represents Ontario education workers, both also pointed to added stresses as reasons for workers taking more sick leave.

Education Minister Mitzie Hunter said the responsibility for attendance management rests with school boards.

Lysyk recommends that school boards develop and implement attendance support programs, including absence reporting, tracking and data analysis.

She said in her report that the direct costs of absenteeism include paying for replacement workers, such as substitute teachers, resulting in less money being available for student services.

The study found that overall sick leave paid as a percentage of payroll increase from an average of 4.22 per cent in 2011-12 to 5.28 per cent in 2015-16, which is an increase of 25 per cent.