Tory Party Chairman Grant Shapps has said "all options are on the table" for pre-General Election debates, amid reports Ukip leader Nigel Farage could be included next year.
The Sunday Times reported Prime Minister David Cameron was open to a "2-3-5" format drawn up by his aides.
Under the plan, Mr Cameron would hold one head-to-head debate with Labour leader Ed Miliband - as the other potential prime minister - a second, which would also include Liberal Democrat leader Nick Clegg, and a third with Mr Farage and the Green party leader Natalie Bennett.
Speaking on the Sky News Murnaghan programme, Mr Shapps said negotiations on the format and timing of debates would not begin until the autumn.
But he said: "We think the debates were a good innovation, they were something new at the last General Election.
"There was a bit of a problem they all took place during the General Election, people across the country didn't get to see the party leaders and the debate properly in their local area.
"It's quite possible not to bunch them up in a campaign now we know the election date is May 7.
"Beyond that there is no negotiations under way, that will have to wait until the back of this year.
"All options are on the table right now."
The Sunday Times said one of the debates would be held during the campaign, with the others beforehand.
Responding to the report a No 10 source said: "It is speculation on what might happen in talks that are not going to happen for several months.
"We have not ruled anything in or out, so that means people can speculate what might happen in the talks.
"But the reality is these talks are several months away."
Last month the Labour leader said the previous format of three debates between the three main party leaders over three weeks should be a "starting point" but that he was open to moves such as a less formal setting and greater voter participation in any repeat of the 2010 confrontations.
He used a Radio Times article to call for immediate negotiations, accusing his main rival of being the "single biggest obstacle" to them going ahead and suggesting the Tories were keen to deny his cash-strapped party vital publicity.
Britain's first such debates, between Mr Cameron, Gordon Brown and Mr Clegg, were staged on the BBC, ITV and Sky News in 2010 after prolonged negotiations between the parties and the TV companies, which resulted in very strict rules on the style of questioning and the division of time for leaders' answers.
Mr Cameron has since complained that they "took all the life out" of the campaign amid constant speculation over whether the practice would be revived, and if so in what form.
Mr Farage repeated his challenge to the Conservative leader in response to claims he was "chicken" for ruling out a run at Parliament in the Newark by-election.
The Ukip leader said: "Mr Cameron said ... that I was a chicken. Well, I'll tell you what Dave, why don't you come on telly and do a debate with me?"
Opinion polls suggested Mr Farage beat Mr Clegg in two debates ahead of this month's European elections.
Mr Farage said: "What David Cameron does, very often he makes these promises, vague promises, and then doesn't actually deliver afterwards."
He told BBC1's Andrew Marr Show: "I don't think he has got any intention of allowing me into any of these debates."
Mr Miliband told the programme it was "up to the broadcasters who they invite, whether they invite Nigel".
He said: "My main desire is that the debates go ahead. The Prime Minister doesn't own these debates, the British people own these debates and he can't wriggle out of them."