Left-wing members of Labour's ruling National Executive Committee (NEC) intend to tackle Mr Blair over the series of rows about the selection of party candidates for London mayor and the Scottish and Welsh assemblies.
A new controversy over the determination of the leadership to impose its will on the party broke out over a plan, disclosed in The Independent yesterday, to force sitting MPs to appear before a selection panel before they can stand again. Critics protested that it would become a "loyalty test".
Despite fears among some ministers that Mr Blair is fighting internal battles on too many fronts, the Prime Minister will make an uncompromising defence of his strategy at today's NEC meeting.
He is so keen to answer the allegations that he is a "control freak", he also plans to make an unscheduled address to Labour MPs on the issue.
Mr Blair will make "no apology" for showing strong leadership. One ally said last night: "He does not want to impose anything from on high, but he does want structures which ensure a disciplined and effective party."
But Mr Blair's authority will be challenged by the four left-wingers who were elected to the NEC in September againsthis wishes. They attend their first meeting of the executive today, which takes place amid allegations that party officials want to "gag" them by imposing a code on how NEC members handle the media.
Mark Seddon, one of the left-wingers, said last night that he would not be bound by the code.