"Contractors from Trility and Fulton Hogan worked throughout the night to repair the pipe. It was fixed at 4.30am this morning," Rotorua Lakes Council said in a statement.
"While repairs were underway, sucker trucks were used to pull wastewater away from the broken section to reduce any further flow into the lake.
"While we want to avoid any contaminant entering our waterways, in the context of the lake which contains some 800 million cubic metres of water, this was a relatively small amount."
Stakeholders and contacts were notified overnight to minimise health risks, and signage has also been placed from Waiteti to Kawaha Point.
"After further discussion with Toi Te Ora Public Health this morning, the health warning has been extended to the whole of Lake Rotorua," the statement said.
"As a precaution, the temporary health notice will be in place until further notice and regular testing of the lake water will take place during that time.
"Signage is in place around the lake to advise the public about the warning."