Rio Olympics chiefs say the diving pool water should change back to blue today after being green for last night's competition.

Alkaline levels are being blamed, with suggestions that athletes who have been using things like suncream have changed the PH level of the water.

"It will be blue from now on," Rio 2016 spokesman Mario Andrada said.

However, officials insist the green water wasn't a health risk.

"It's not really dangerous. It's not like it's toxic or dirty or any of that. I think that the filter is busted, but I'm not sure," Canadian team leader Mitch Geller had said.