The Scottish National Party and Plaid Cymru have called for a 'progressive alliance' government for Britain, involving themselves, Labour and the Liberal Democrats.
The Green Party's first MP, Caroline Lucas, who is leader of her party in England and Wales, and who won the Brighton Pavilion seat on 6 May, would also be invited to come on board.
The left-wing nationalists say they are willing to explore "the potential of working with other parties to ensure the new UK Government serves the best interest of both Scotland and Wales."
Plaid’s Leader Ieuan Wyn Jones, and the SNP Leader and Scotland's First Minister, Alex Salmond, have already accepted the offer made by Prime Minister Gordon Brown of ‘civil service support’ which would be crucial in the event of discussions being held to examine options for a new government.
Both leaders have agreed that they will now seek to explore an outcome which will reflect the political choices made by the progressive majority of both the people of Wales and Scotland in the General Election.
The move comes while media attention is focused on the negotiations between the Conservatives and the Liberal Democrats about forming a government.
The progressive left pressure group and thinktank Compass has also been canvassing the 'progressive alliance' idea among Labour and trade union activists.
This announcement was made by the SNP and Plaid Cymru (the Party of Wales) in light of yesterday’s statement by Gordon Brown that he would be willing to speak with any of the party leaders.
Plaid and the SNP declared: "We believe that following the outcome of this election, their parties have a responsibility to work towards the aim of creating political and economic stability and to secure a positive outcome for their nations."
Mr Salmond declared: "The assumption that a Tory/Liberal Democrat pact is inevitable is not correct. There are alternative and more progressive options available if politicians have the will to seize the moment."
The BBC's political correspondent, Nick Robinson, commented on his blog: "An arrangement between Labour, the Lib Dems, the SNP and Plaid could command a majority in the House of Commons. The nationalist parties would, of course, extract financial and political concessions from Westminster."
But a Labour spokesperson dismissed the notion, accusing Mr Salmond of a "desperate" ploy to keep himself in the political game.
Critics in turn, suggested that Labour's hierarchy was being tribal and conservative, and condemning itself by refusing to think beyond its own immediate interests.
Both Plaid and the SNP have appointed teams to examine the mechanics of any future discussions with their dedicated UK liaison officials in London.
The SNP's team will be led by their Westminster leader, Angus Robertson MP and Deputy Westminster leader, Stewart Hosie.
The SNP Leader and Scottish First Minister, Alex Salmond said: "A balanced parliament is redolent with opportunity for Scotland. At the start of the General Election campaign, the SNP and Plaid Cymru pledged to fight for the best deal for Scotland and for Wales."
He added: "We now find ourselves in a position to make real gains. Working together, we will use our votes and experience of negotiating in a balanced parliament to maximum effect to take Scotland and Wales forward."
Plaid’s leader, Ieuan Wyn Jones said: “Plaid has a track record in putting aside our own party political interests in order to work with other parties to deliver the best outcome for the people of our nation. That is what we did in Wales in 2007 when we formed a coalition with Labour which is widely acknowledged to have been a tremendous success.
"We will now do what is expected of us by the electorate and explore the potential of working with other parties in Westminster in order to achieve the best deal for Wales. A more balanced Parliament is a real opportunity to bring about a new approach to politics in the UK which would be welcomed throughout the nations of these islands.”
On election night, Dr Lucas, for the Greens, said that she was likely to follow the lead of other Green parties in Europe, who seek a policy-by-policy approach to cooperation in a balanced parliament situation.
But she agreed that the Greens' values and policies put them in more sympathy with the left of the political spectrum.