Popular Otago swimming spots will be monitored from today - to keep an eye out for dodgy bacteria

The Otago Regional Council says they'll be keeping a close on locals' favourite summer spots until the end of March.

They'll be testing for a selection of bacteria that can cause upset stomachs and eye irritation.

A spokesperson says Otago's water quality is usually pretty good - but rain can wash all kind of contaminants into the water.

The general advice is to stay out of the water for two days after heavy rain.