The North Coast's director of public health says COVID-19 fragments found in sewage in Ballina and Lennox Head are of great concern, given that three people who have since tested positive to the virus travelled throughout the region.
Paul Corben said the samples were collected on August 12 from the two adjoining communities of Ballina and Lennox Head, taking in almost 40,000 people.
Last week it was revealed Sydney man Zoran Radovanovic travelled to Byron Bay and other parts of the Northern Rivers with his two teenage children while infected with the virus.
Contact tracers have struggled to track the movements of the man and his children, who are being treated at Lismore Base Hospital, because they failed to check into venues they visited before testing positive.
"We are still in the wake of identifying three cases amongst people who travelled here from Greater Sydney and they have not left a clear trail of where they've been," Dr Corben said.
"We are not out of the woods yet.
Health authorities are urging people who may have been unknowingly exposed, with even the most mildest symptoms, to come forward for testing.
