Brownes Dairy will face court in Bunbury, Western Australia after up to 140 thousand litres of milk was allegedly spilt into the Brunswick River.

It will also be alleged the incident caused the death of fish and other aquatic wildlife and resulted in a clean-up operation involving the removal of an estimated 36 million litres of mixed river water and milk from the watercourse.

The Department of Environment Regulation has started a prosecution against the company based in Brunswick Junction, between Harvey and Bunbury.

It will be alleged that on the night of November 27 and 28, 2011, the company caused or allowed a discharge from its premises of an estimated 70 to 140 thousand litres of unprocessed milk which entered the Elvira Gully watercourse — a tributary of the Brunswick River.

The company has been charged with causing pollution and serious environmental harm and will face Bunbury Magistrates Court on February 17.  

A Brownes Dairy spokesperson said the company responded immediately, devoting significant resources and attention to the incident.  

"Since then we have cooperated with the Department of Environment and Conservation as they followed their process and investigated the incident," they said.