The operator of the national electricity grid will move this week to relaunch its contentious upgrade of the regional power network as it seeks to boost public support for the initiative.

EirGrid, the State-owned network company, plans within days to unveil an underground route for the Grid West element of the project, between points in Co Roscommon and Co Mayo.

The feasibility of this 113km underground corridor will be examined side-by-side the existing overhead pylons route before the go-ahead is given to proceed with either.

The pylons plan has been estimated to cost €240 million but the cost of the underground alternative remains unclear.

The development comes on foot of a storm of protest against pylons from farm, tourism and environmental groups, which emerged as a major political issue last year for both Fine Gael and Labour.

This led the Government in January to appoint an independent panel to carry out a detailed examination of whether cables could be put underground.

After a big setback in the local and European elections last month, the question remains acutely sensitive for both Coalition parties.

The grid plan is already a target for the Opposition and the Government is keen to minimise any further political damage from the initiative in the run-up to the general election. With reliable access to high-volume electricity a key demand for many major investors, the grid upgrade is also seen to be crucial to attempts to boost job creation in the regions.

The basic objective behind Grid West is to connect the north Mayo area with a strong point on the transmission system near Carrick-on-Shannon.

The underground route would link Flagford, Co Roscommon, and Moygownagh, Co Mayo, which have been identified as end points for the Grid West pylons plan. The routing of cables underground would loosely track the road connection between both locations, it is understood.

EirGrid plans an extensive information campaign to explain to local people how the plan would work.

The corridor for the pylons plan runs west of Ballina, east of Foxford and Swinford and south of Charlestown and Ballaghaderreen.

The imminent release of an underground route for the Grid West plan will be followed in coming months by the publication of an underground route for the Grid Link project, connecting Co Kildare with Co Cork via Co Wexford.

The Government has directed EirGrid to develop comprehensive underground options for both projects to the very same level of technical detail as carried out for pylons.

Such proposals will be examined by the panel chaired by former Supreme Court judge Ms Justice Catherine McGuinness, the aim being to provide reassurance to the public that all options are considered fairly and in a transparent manner.

The panel must assess the question of cost, a crucial concern given repeated Government claims that underground cabling costs would be significantly higher than pylons and feed through to increased electricity prices for both business and domestic users.

The panel must also examine the technical efficiency of the underground route and any potential environment impacts.