Police are investigating claims protesters opposing the Roe 8 highway extension have tried to take down police horses after a wire trap was found in bush within the construction zone.

As tensions over the contentious road project escalate, police said they had found what appeared to be a tripwire suspended between several trees in the Beeliar wetlands.

The wire was arranged as a “web”, leading police to believe it was designed to maim or kill horses being used by the police mounted division to keep a lid on protesters’ activities.

Play Video More than fifty per cent of people support the project. The West Australian Video More than fifty per cent of people support the project.

Although police said little about the investigation, it is understood an officer riding police horse “Matilda” found the wire after inadvertently stumbling into it.

It was only quick thinking by the officer to back away from the trap that saved the horse, which may have needed to be put down if the wire had severed its tendons.

Camera Icon Police Horse Matilda (right) among protesters. Credit: The West Australian, Michael Wilson/The West Australian.

Environment Minister Albert Jacob told 6PR radio that setting a tripwire was a serious matter and it was only good fortune that no person or animal was hurt.

“I can’t say too much because WA Police have an active investigation on,” Mr Jacob said.

“It’s a very concerning development.

“I’m glad that this was discovered before anyone got hurt but (it is) a very concerning development down there on that site.”

After clashes broke out between officers and protesters trying to stop construction workers from clearing bushland for the project, police have deployed to the mounted division in a bid to keep the peace.