Labour is "ready for an election whenever the PM calls one", party vice chairman Martin Salter has said.
The prime minister could call an election at any time up to spring 2010
Adding to recent speculation about a snap election, the MP said the party was on an "election footing" - but denied there was a timetable in place.
According to the Times newspaper, PM Gordon Brown has launched a fundraising in case he plumps for an autumn vote.
Speculation that Mr Brown might call an autumn election has been fuelled by a surge in Labour's opinion poll ratings.
Mr Salter said: "We have been put on an election footing and preparations are under way so that we are ready for an election whenever the Prime Minister chooses to call it." Positive polls
Liberal Democrat leader Sir Menzies Campbell has said his party is ready for an election and speculated Mr Brown might announce a date during the party conference in September.
While the expected date of an election remains May 2009, Sir Menzies said there was a "one in six" chance of an autumn election and a 35% chance of a May 2008 poll.
Conservative leader David Cameron has also said his party is ready for any snap election with work being done on a manifesto and a host of policy groups due to report in the next few weeks.
The UK prime minister can call an election at any time up to May 2010. Recent practice has seen an election every four years, which is why May 2009 is still seen as the most likely date.