Fianna Fáil and Fine Gael are prepared to make major concessions on climate change to lure the Green Party into government.
The Civil War parties are prepared to consider significant shifts in policy that would likely require a million electric cars on the roads within five years, and greater investment in public transport.
It would also see more than 500,000 homes retrofitted, a dramatic cut back in the use of fossil fuels for electricity and heating, and increases in carbon tax.
Fianna Fáil and Fine Gael both responded positively to a set of demands set out by Green Party leader Eamon Ryan in a letter yesterday, including an ambitious target to reduce Ireland's greenhouse gas emissions by at least 35pc over the next five years.
This would mean doubling the emissions reduction target of 3.5pc per year in the existing Climate Action Plan, which will almost certainly be overhauled by the next government.
Fianna Fáil leader Micheál Martin said there was now "a lot of common ground" between the parties, while Tánaiste Simon Coveney also welcomed Mr Ryan's letter.
The two parties are anxious to establish a stable government within weeks to deal with the ongoing Covid-19 crisis. Historic talks between the three party leaders will likely take place in the coming days.
"Everyone needs to knuckle down in May to get this done," a senior Fianna Fáil source said. A Fine Gael source said it was "game on" for the talks.
Mr Ryan said forming a government should take "a short number of weeks" if Fine Gael and Fianna Fáil respond adequately to his letter. He said an annual reduction in carbon emissions of at least 7pc is a red line for the Greens.
"If we were trying to go into government where it wasn't being really ambitious around climate, I think it would be very hard for us to get through our members - not only that, but even through our parliamentary party," he said.
This would likely mean fast-tracking existing plans to roll out one million electric vehicles, upgrade 500,000 homes, make electricity 70pc renewable and increase carbon tax to €80.
These are all outlined in the current Climate Action Plan, but commits to introduce them over a decade.
Speaking on RTÉ's 'Six One News', Mr Martin said: "There seems to be emerging common ground on key themes.
"We'll have opportunities as a result of Covid-19 as to change the nature of society into the future, particularly in terms of housing, in terms of healthcare, and in terms of a green new deal."
Mr Coveney said Mr Ryan's letter was "a welcome and serious response" to the framework document.
"We'll work to ensure it's the beginning of a productive engagement," he tweeted.
Mr Ryan's letter also calls for the two parties to commit to ending Direct Provision; introduce a universal basic income trial; build public, social and cost-rental housing on public lands; a timeline on a referendum to cap land prices; an ambitious programme of offshore wind energy; and ending offshore gas exploration.
However, newly elected Fianna Fáil TD Norma Foley said she opposed the Greens' key demand that construction on all new fossil fuel infrastructure be halted, especially if it is for liquefied natural gas.
Ms Foley has said she will oppose any plans to stop the construction of a new natural gas pipe plan in Ballylongford, Kerry.
"This is something I'll be raising with Micheál and the parliamentary party," she said.