Bathurst Regional Council announced just after 1pm on Thursday, March 28 that blue green algae had been detected at levels requiring a red alert to be issued.

As a result, the dam has been closed to the public until further notice.

While people can be on the banks, no water-based recreational activities, including boating, are permitted at the dam.

The council said it will follow protocol around the management of the dam.

To be able to reopen the dam, the council requires two consecutive tests that detect algae at the amber alert level.

The council said it is likely that the closure will last at least 10 days, however, it could be much longer depending on the results of subsequent water testing.

The Bathurst town water supply remains safe to drink while the red level alert is in effect.