An Auckland high school has told its students they are not allowed to go to the toilet during class time - unless it is urgent.

Lynfield College, in Mt Roskill, this week introduced a new rule that no student is to leave class to use the bathroom facilities or to get a drink.

A notice was posted on the school's Schoology page - an app that allows teachers to post notices about assignments and the likes, to inform and communicate with students - yesterday morning.

"There is to be NO LEAVING CLASS FOR TOILET OR DRINK BREAKS,'' the note read.

"There is enough time in between class and at interval and lunch to use the bathroom and have a drink. There is no need for you to leave class to do this.

"Be responsible for managing your time better at breaks to take care of these needs.''

The Ministry of Education allows school boards to make their own rules and there is currently no national policy on toilet breaks in this regard.

Auckland's Lynfield College is cutting back toilet and drink breaks during class time. Photo / Supplied

A year 12 female student said many students were surprised when the notice went out; given there had not been any previous warning, she said.

"I think we should just have the freedom - when you gotta go, you gotta go. You can't really plan out your toilet breaks.''

The senior said the news was of particular interest to female students, who felt there could be hygiene issues associated with the ban.

"A lot of students posted [on the notice] and were like: 'How are we supposed to change our tampons? Are we supposed to change it in the back of the class'?

"But the teachers just deleted it.''

Principal Cath Knell acknowledged that the new rule came about due to several students claiming to want to use the bathroom repeatedly during class time.

With exams starting next week, it was becoming an issue.

"Over the past couple of weeks, we have had some students interrupt this preparation time by distracting others from their learning.

"A number of these students have being using the excuse of 'needing a drink' or 'needing to use the toilet' as their reason for being out of class.

"As we want all our students to be able to do their very best in their assessments, we appealed to staff at briefing this morning to encourage students to use facilities between classes, during intervals or lunch times - unless in the case of urgency - so they minimise the disruption to their own learning and the learning of others.''