The SNP have welcomed a U-turn by broadcasters to include Nicola Sturgeon in the proposed general election TV debates.
But there is still confusion over whether the highly-anticipated showdowns would go ahead.
David Cameron is under increased pressure to take part after the Greens were also given a place.
The Prime Minister has threatened to boycott the debates without the Greens, who many Tories believe will help split the left-wing vote.
The Democratic Unionist Party (DUP), who could hold the balance of power in May, have also angrily demanded a spot, pointing out that they have more MPs than many of those who have been included, such as the SNP.
The First Minister said that reports of her party's inclusion in the proposed debates were "very welcome progress indeed".
Angus Robertson, the party's leader at Westminster, said that the SNP's case had been "unanswerable".
With the possibility that SNP MPs will be kingmakers at Westminster after the general election, Mr Robertson said it was only fair that people in England as well as Scotland heard their views on austerity, cancelling Trident, and achieving new powers for Scotland.
It is understood that the SNP had been seriously considering legal action had they been excluded.
Under the new plans, BBC and ITV would each stage a seven-party strong debate with the Tories, Labour, Lib Dems, Greens, SNP, UKIP and Plaid.
Sky and Channel 4 would also still host a head-to-head between David Cameron and Ed Miliband.
Opponents have accused Mr Cameron of "running scared" of the debates and of politically motivated support for the Greens, who are likely to take more votes from Labour than the Tories.
Some senior Conservatives blame the 2010 leaders debates for their party's failure to win that election.
Asked if the new 7-7-2 format would guarantee Mr Cameron's participation, a Conservative source said: "Further discussions are planned and we will obviously look at any new proposals presented by broadcasters."
DUP leader Peter Robinson said he would be writing to the BBC and ITV demanding an explanation for his party's exclusion.
The SNP have 6 MPs, Plaid have three, Ukip two and the Greens just one, while the DUP have 8.
George Galloway, the former Labour MP who holds a seat in Bradford for the Respect Party, also posted on Twitter: "Oi - what about me?"
BBC director general Tony Hall told the Radio Times it made "absolute sense to have the involvement of the Scottish National Party, Plaid Cymru, the Greens and Ukip".
"This time round the debates are going to be more important to democracy than last time round," he said.
"I don't know anyone who can call this election, therefore the notion of hearing those who are competing for your vote being tested and testing one another, is much more important than last time round."
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