Cockburn Cement has been found guilty of emitting unreasonable emissions from its plant after a long-running campaign by nearby residents who claimed they were confined to their homes due to the strong stench.

Greg Hocking, Cockburn Pollution Stoppers told Oliver Peterson on Perth Live that he's been involved in this issue since November/December 2016.

"It's been a long time coming for this final decision on prosecuting the company," he told Oly

"The situation has not improved since some years ago, the main problem is when the summer sea breeze comes in, you get this strong sulphurous odour come from the factory and that hasn't changed at all, we still having our lifestyles interrupted."

The Adbri subsidiary was found guilty on six counts and acquitted of the remaining seven charges, after Magistrate Heidi Watson said she was satisfied the emissions had caused inconvenience and unreasonably interfered with the amenity of residents.