A group of Blairite Labour ex-ministers is planning to set out its own policy agenda in the run-up to the party's annual conference next month.
The move is a bid to fill what it regards as a "policy vacuum" in Government.
The group, which served in Tony Blair's administration, insists that the initiative is intended to focus attention on the policy challenges facing the Government, rather than the question of Labour's leadership.
But it will inevitably draw attention away from Gordon Brown's expected drive to reassert his authority with an economic recovery plan and a possible reshuffle following the summer break.
The Financial Times newspaper reported that Mr Brown is working with energy companies on a package that would deliver hundreds of millions of pounds to protect poor families from rising fuel bills, but stop short of the windfall tax on utilities demanded by many backbenchers.
Despite his political difficulties and poor poll ratings over the past year, the Prime Minister has largely been spared sniping from ex-ministers from the Blair era, who have kept a low profile since the handover of power.
But some commentators believe the leaking of a private memo by Mr Blair, attacking Mr Brown's "lamentable" performance as PM, may act as a green light for critics to surface.
The unnamed former ministers are expected to use a series of newspaper articles and speeches in the coming weeks to set out ideas on a wide range of issues which could include public sector reform, national identity or the balance between civil liberty and national security. "There's a big policy debate we should be having in addition to talking about the leadership," said one of them.
Labour MP Jon Trickett urged Mr Blair to stop "disgraceful" efforts by his supporters to undermine the Prime Minister.
Mr Trickett told the Daily Express newspaper: "I'm not alone in finding the timing of this leak and these articles all a little suspicious. It looks like a calculated attempt by a handful of ultra-Blairites to damage and divide the party at the very time we should be uniting behind Gordon Brown to deal with the nation's problems."
