Sunderland teachers took an average 6.2 sick days last year - higher than the national average.
Statistics released by the Department of Education for 2013-14 and the average nationally is 4.3 days and regionally 4.4 days.
Chris Keates, general secretary of teaching union the NASUWT, said: “It is dangerous and misrepresentative to make an overly simplistic analysis of these figures as often the number of days lost can be influenced by a small number of teachers who may have serious long-term illnesses.
Sunderland topped a regional league table,, Middlesbrough was second, with 5.5 days lost per teacher, and South Tyneside third with 4.9 days.
Coun Pat Smith, Portfolio Holder for Children’s Services, said: “Only teachers in Sunderland’s 63 maintained and voluntary controlled schools are employed by the council. The remainder of the city’s 117 schools are either academies or voluntary aided schools which employ their own teaching staff.
“The most recent absence data shows a reduction to 4.7 days for teachers in maintained and voluntary controlled schools in 2014/15, compared with that in the league tables based on data from 2013/2014.
This reflects a steady decline in teacher sickness absence rates.
“This is attributable to close working relationships between the schools and the Local Authority and a consistent and robust application of an Attendance Management Policy which promotes attendance at work while supporting health and wellbeing.”