TORONTO - A work-to-rule strike by Ontario's public elementary school teachers means they are not participating in training on the province's new sexual-education curriculum.

Schools remain open and extracurricular activities and field trips continue for now, but teachers won't administer standardized tests, add comments to report cards or participate in any professional development related to Ministry of Education initiatives.

The president of the Elementary Teachers' Federation of Ontario says that includes training on any new or revised curriculum document, including the revised health and physical education curriculum.

Sam Hammond says the union supports the new curriculum, but the work to rule will continue until the government takes what he calls "offensive concessions" off the table.

The sex-ed curriculum was last updated in 1998 and the new version, which will be taught in schools starting in September, has prompted thousands of parents to protest, saying the material is not age appropriate.

Education Minister Liz Sandals says it would be preferable for teachers to attend professional development on the new curriculum, but if not, they'll have more work to do over the summer on their own to prepare.