Transmission Company Victoria is launching environmental surveys on public and private land to help pin down the final route for the controversial transmission line from near Ararat to cross into NSW near Kerang.

Governments have set a 2025 deadline for the selection of the final 70 metre-120 metre easement needed to locate the 500 kilovolt double-circuit overhead transmission line carried by towers about 80 metres high.

TCV earlier this month narrowed down the proposed route from 50km wide to 2km wide.

There are about 350 private landholders within this new route

The project, which continues to spark angry protests across regional Victoria, aims to connect the Victoria and NSW energy grids.

These initial studies will extend from public land into "a small number of private properties", TCV has said.

Opponents and representative groups like the Victorian Farmers' Federation have advised landholders TCV does not yet have a legal right to access farms.

TCV has offered to pay landholders $10,000 for access.

"Our land team will negotiate access agreements with landholders, including biosecurity requirements, before any field surveys commence," TCV says.

Attempts to access private land have met with continued resistance.

Late in August, two TCV workers were involved in what TCV called "a threatening incident" west of St Arnaud where police were called.

The pair claimed to have been on a public road heading to an appointment with a landholder when they were surrounded by a group of people who blockaded their car with vehicles and farm machinery.

"We understand that some people are strongly opposed to VNI West, and we respect their views and their right to peacefully protest," VNI West project director Sam Magee said.

"It is disappointing that individuals have been personally targeted as they go about their work, and we ask that the safety of our people be respected."

TCV says field surveys are now necessary to "refine" its proposed route.

It says survey teams will undertake ecological surveys on public land including roadside reserves, looking at remnant native vegetation and other areas of ecological interest.

"Data gathered from these surveys will add to TCV's understanding of the flora and fauna across the draft corridor and support the work underway to find the best location for the VNI West line with the least impact on farms, the environment and local communities," TCV said.

The power company said the small team of ecologists may be spotted by local community members as they drive on local roads, stopping frequently to assess, walk around and photograph the vegetation.

TCV needs to progress the studies as part of the environmental assessment required for the project under government regulation.

"The site investigations will continue for several months, requiring visits to multiple locations as specialists document vegetation classifications, assess their conditions, and explore the potential presence of specific flora and fauna.

"The purpose of these surveys is to understand the current conditions within the corridor."

The company says it wants to further refine the route for VNI West which "has the least impact" to agriculture, cultural heritage and values, rural communities and the environment".

"Input from the community and landholders is a critical part of that process," it says.