The Labour Party's election coordinator Douglas Alexander has dismissed reports that Gordon Brown could announce a snap election this week.
He told BBC News 24's Sunday programme the speculation was "nonsense".
Mr Alexander said he had read stories about the Conservatives planning a poster campaign with "incredulity".
He would not rule out an election this year but said an election would not be announced in the "next two, three, four, five or six days".
Mr Alexander, who is also international development secretary, has just returned from Afghanistan.
He said: "If the election coordinator was in Afghanistan last week it's not very likely we'll announce an election this week.
"The claim that the Conservatives made that we are announcing an election this week, it's no surprise, is nonsense."
Mr Alexander emphasised his party would be prepared for an election whenever Prime Minister Gordon Brown decided the time was right.
He said: "My job is to make sure our campaign, our party, is ready, whenever the prime minister decides to go to the country.
"I will make sure we are ready whenever the starting gun is fired."
He said the reports about an election had been put out by the Conservatives "to mask their own difficulties".
He said: "There's a genuine power struggle taking place within the Conservative campaign.
"David Cameron did have a political strategy, he's been knocked off that strategy by the success of Gordon Brown."
Speaking to Sky News, shadow foreign secretary William Hague said: "It is our job to be ready for a general election.
"We would like to see a general election and for this country to get the change of government it really needs. We are ready for it.
"Gordon Brown, if he calls that election, is in for the fight of his life."