Yet another popular Canterbury swimming spot is closed to the public due to toxic algae

The Canterbury District Health Board has issued a public health warning for the Ashley River at State Highway 1.

Medical Officer of Health Dr Ramon Pink says people and dogs should avoid the area.

He says the algae looks like dark brown or black mats - and exposure may cause rashes, nausea, stomach cramps and numbness.

With at least four warnings in place in the Christchurch area - locals are urged to check ECan's website before they swim in the region.