Chief executive Scott Hawkins said the cause of the water imbalance was due to equipment failure.

“Most likely caused by the unprecedented heat conditions,” he said.

The imbalance reacted with chlorine in the water and staff closed the pool as a precaution.

“Some patrons at the time had difficulties in breathing.”

Staff then commenced rebalancing the water.

The hot artesian pools and 50-metre pool re-opened at 11am whilst the program pool and hydroplay re-opened at 3pm, when the water was deemed safe.

“The Moree Artesian Aquatic Centre apologises for any inconvenience this may have caused.”