The agency is currently building a new pipeline from Ravenswood to Dandalup, much of which will be laid next to many farming properties.

But Rod McKay - who runs about 100 head of cattle on his 120 hectare property - claimed construction workers were taking liberties and operating beyond the limits granted to them by the Environment and Conservation Department (DEC).

The pipes will be built on government land running alongside the properties, but because the easement is so narrow (about 10m), the government needs to annex some adjacent land from private properties for the construction works.

“Apparently, they have a permit which allows them to work 15m into my property,” Mr McKay said.

However what angers Mr McKay most is that the work has extended beyond the 15m to almost 30m into his land.

“The works are being carried out in an environmentally sensitive area,” Mr McKay said.

“The land had much natural vegetation which I wanted to protect.

“Furthermore, there are no sanitary or hygiene mechanisms in place to wash the equipment down.

“They could have brought diseases such as dieback into the area.”

But Water Corporation communications coordinator Clare Lugar said a copy of the necessary clearing permit was available on the DEC website.

"For safety reasons, we have installed a temporary fence between 25m-30m from the property boundary which may give the incorrect impression that we intend to clear to that fence,”she said.

Ms Lugar also said that the area of native vegetation on the property was not deemed an Environmentally Sensitive Area under the Environmental Protections (Clearing of Native Vegetation) Regulations 2004.

“But we recognise that dieback is a significant concern,” she said.

“The contractors undertaking the works are required to use hygiene management in accordance with the conditions of the clearing permit and planning approval.

“Washdown areas are in place and in use.”