The Asthma Friendly Schools Project aims to help the estimated 65,000 school students with asthma breathe a little easier while trying to work at school.

"Asthma is the most common cause of school absenteeism, affecting one in four primary students and one in seven high school students," Mimi St John Austen of the NSW Asthma Foundation said.

"An asthma friendly school involves the whole school community in providing a more supportive and understanding environment for students with asthma.

"It is important students do not risk an attack because they were too embarrassed to use their puffer in front of their peers."

For schools to be designated as "asthma friendly" they need to encourage students to carry their own reliever medication, have an asthma first aid kit on site at the school, provide asthma emergency training for staff and teach an asthma program in the school curriculum.

Asthma Foundation education officer Melissa Perrett visited Southern Highlands Christian School and St Thomas Aquinas primary school to train staff in emergency asthma treatment.

She also visited Bowral High School, Chevalier College, Moss Vale High School and Mittagong Public School to register them for the project.

The Asthma Foundation said the strategies were aimed at improving self-management skills in students with asthma to help them participate confidently in school activities as well as cutting back absenteeism and emergencies due to asthma.