The budget for transport in the National Development Plan is going to be €35 billion up to the year 2030, RTÉ News understands.

Most other sectors will have their budgets curtailed to the year 2025.

However, transport will be treated differently on acount of the long lead-in times for such projects.

Of the €35 billion, it is understood the breakdown is €12 billion breakdown on public transport, €6 billion on roads, €4 billion on walking and cycling and €13 billion on maintenance.

Housing is the other sector which is expected to receive significant funding under the plan.

Part of that would involve an extensive budget for building retrofits.

Homeowners will be encouraged to undertake such work via a mix of both grants and very low interest loans

Furthermore, all of the capital projects contained in the Government's €165 billion National Development Plan, which is due to be published in Cork tomorrow, will be divided into one of three catagories - depending on their climate impact.

RTÉ News understands that this new innovation is aimed at ensuring both the environmental cost and the financial cost are taken into account in the the 180-page document.

The seven headings by which each project is assessed include climate mitigation, climate adaptation, water, air, waste, nature and Just Transition.

On that basis of that, the project will be determined to be either having a favourable impact, no significant impact or a negative impact on the environment.

It is understood that all of the road projects contained in the 2018 National Development Plan have been included in the updated plan.

However, the Programme for Government commitment to invest twice as much in public transport over roads is being adhered to.

This capital infrastructure plan was signed-off by the Cabinet last July - and involves €136bn coming from the Exchequer and €29bn from other State bodies.

That is an increase of €45bn on the existing plan.

Over the past number of months, the detail has been finalised - including each Government department receiving a five-year capital allocation.

It is understood that rather than each project being given an individual price-tag, they will be placed instead in what are called "cost-categories" or bands.

Given the cost of a project often cannot be determined until it goes out to a competitive tender, the Government feels that it is preferable to avoid giving specific costs on individual road or rail projects.

RTÉ News understands there will be a firm commitment to Dublin's proposed MetroLink in the document.