The trade unions have been put on standby for an imminent general election announcement, it is reported.
Mr Brown has refused to rule out an autumn election
The Times newspaper says Labour has asked the biggest unions to pay next year's party affiliation fees now - raising about £6m upfront.
It also says unions have been asked to make their call centres available to the party this weekend.
During Labour's conference last week Mr Brown repeatedly refused to rule out an autumn election.
He was thought to have spent last weekend considering whether to go to the country.
Mr Brown does not have to hold an election until 2010 - but Labour's continued lead in the opinion polls has led to speculation he will go early - with dates at the end of October and the beginning of November being mentioned by pundits as the most likely dates.
The Conservatives and Lib Dems have both said they would welcome a snap poll.
Last week the BBC revealed the Labour Party had started recruiting campaign support staff and the party's treasurer, Jack Dromey, told the Labour conference he was "confident of our capacity to be ready" for an election.
The BBC's political editor Nick Robinson said there had been a "lot more fundraising" in the Labour Party in the last 24 hours.
Meanwhile the Conservatives have been outlining some major policy pledges - pledging to up the inheritance tax threshold from £300,000 to £1m and to abolish stamp duty on properties worth less than £250,000.
And the Electoral Commission has sent out guidance to returning officers at local councils to alert at least 1m people who may be left without a vote, if there is an early election - including those who have moved home recently or those who have just turned 18.
Commission chairman Sam Younger said: "The bottom line is that calling a general election is a political decision.
"Those that administer the elections must be ready to organise that election whenever it is called, according to the rules."
The prime minister is also expected to make a statement on reducing troop levels in Basra to the Commons next week.