The school sent an email to parents and carers on Thursday, warning them of the pertussis outbreak, pointing families to ACT Department of Health information and urging parents to see a doctor if they suspected anyone in their family had caught the disease.

Principal Dee Whitby confirmed two primary school pupils from separate families had contracted whooping cough.

One of the children was on holidays at the time and had not been at school since catching the disease.

But the email has met with some backlash from parents concerned the school hadn't been strict enough about vaccinating students.

Ms Whitby said she had been upset by claims the school was lax on vaccinations or anti-vaccination.

"We are not anti-vaccination - anything but," Ms Whitby said.

"We have extremely high vaccinations rates. We have tried to be really responsible.

"It's not a law - you don't have to have your children vaccinated - but if a law came into force we would enforce it."

The two Steiner cases are among 168 confirmed reports of whooping cough in the ACT as of March 28, more than double the number of cases recorded at the same time a year earlier.

An ACT Health spokesman said 70 cases were recorded during the same period in 2014.

Ms Whitby said the school emailed families within a few hours of confirming the two recent cases.

"We contacted all the staff and all the parents," she said.

"Because one of the children became sick on holiday and has not been at school, it's been a bit easier. We just keep providing parents with as much information as we can and keep them informed."

She said the school followed ACT Health guidelines and ran voluntary vaccinations programs, including clinics for pertussis .

"We follow all guidelines from the health directorate - they guide us through everything," she said.

"We roll out an action plan for any infectious disease. We also host all the public [vaccination] clinics available. We offer to host students who go to schools that don't have vaccination clinics."

The ACT Health spokesman said the Health Protection Service regularly liaised with schools if a student was diagnosed with whooping cough.

This included raising awareness of the disease and providing disease control advice, such as periods of exclusion.

"Schools are encouraged to distribute information and place notices in school newsletters if a case of whooping cough occurs in the school," the spokesman said.

The chief health officer wrote to all ACT schools in April after an increase in pertussis cases to provide educators with information about the disease and appropriate disease control measures.

ACT Health recommended all parents and children vaccinate against whooping cough, the spokesman said.

He said the vaccine was administered as part of the National Immunisation Program at two, four and six months of age, with boosters at four years of age and in year 7 at school.

The pertussis vaccine is recommended but not funded for other age groups.