Three Dunedin schools closed early on Tuesday due to a “significant” burst water main which also shut Moana Pool.

Otago Boys’ High School (OBHS) announced on social media it was closing at 11am - affecting exams scheduled in the afternoon.

It had not had water since 8am.

Dunedin City Council Three Waters worker Calvin White said the burst main was in a very awkward spot. 

"We had to be very careful with it …  there is a big power cable going through the middle of the trench where we're working and we have not got a very good shut-off, so there’s lots of water everywhere - but none to drink.” 

He said the pipe was one of many in Dunedin that dated back to 1939. 

While it was in reasonably good nick, it had “gone off” in an inconvenient spot. 

"It's pretty much the same as what happens in just about every other street in the city, but it's just very unfortunate in the place where it is.”

Trinity Catholic College and Arthur Street School were also closed for the day.

In an update on social media, Dunedin City Council said a workaround meant water supply was back on and Moana Pool would reopen by 2pm -however it did not reopen and would instead reopen on Wednesday. 

Moana Pool closed Tuesday after a burst water main. Photo: Gerard O'Brien

Contractors were still working to fix the original problem, which it called a “significant water burst”n Stuart St.

OBHS said it did not take the step to close lightly.

“We are aware of the disruption to students and families, however we feel that the care of the students and staff is most important at this time.

“We have also been in contact with the Ministry of Education regarding this situation.

“Without a water supply, toilet facilities and the canteen cannot operate, making it unsafe for staff and students to remain on campus.”

Morning exams would continue unaffected until noon, but afternoon ones had been cancelled and students were asked to check emails for rescheduling updates.

A Dunedin City Council spokesman said there had been a pipe failure in Stuart St.