Close to 200 protesters were at the plan B highway project site on Saturday. (CBC)

Opponents of a controversial highway realignment on Prince Edward Island have beefed up their presence at the construction zone.

For the third straight day, protesters were making their mark and even setting up shop at the work site. While construction signs are all around them, the plan B protesters remain optimistic they're making progress.

"We've had some minor successes," said Roy Johnstone. "I think we've stopped the construction for three full days now. So we're feeling very good about that."

Machines at the site were just getting started on the Trans-Canada Highway realignment project on Thursday morning when a group of protesters got in the way of some excavators and tree-cutting machines. That forced police to close the work site for safety reasons. The same thing happened Friday, and contractors were told a fence needed to go around the entire site. That's more than six kilometres.

Work crews were back at the site on Saturday, putting in more fencing and erecting "no trespassing" signs — measures to keep the protesters out.

But deep in the woods, protesters have now set up camp. They're hoping the province stops construction of plan B. The province says the existing road is dangerous and a new route would be more efficient for truck traffic. But the protesters don't buy it.

"I don't think that making a road going through this beautiful woodland is the answer," said Mari Basiletti. "I think there could have been other answers."

Meanwhile, Keith Kennedy is settling in for the long haul and he says the group is keeping a close eye on construction.

"If we don't keep an eye on these hemlocks, and this stream, it's obvious that the machinery and the equipment is not respecting the environment," said Kennedy.

The project to realign the portion of the Trans-Canada Highway between New Haven and Bonshaw has been the centre of controversy for months. A watershed group says it is worried construction will cause run-off in the West River, despite assurances by P.E.I.'s environment minister that won't happen.

Protesters say they plan to keep their demonstration peaceful. So far they haven't had any issues with security or the RCMP.