He claimed Mr Blair was "totally responsible" for the briefings adding: "He is the only person who can stop it."
She said the allegations made by multi-millionaire novelist Ken Follett that Labour spin doctors carried out secret briefing on behalf of the prime minister were total "rubbish".
On Sunday, Mr Follett stepped up the attack he had already started on Labour's spin doctors,
blaming the prime minister's official spokesman Alastair Campbell and Northern
Ireland Secretary Peter Mandelson for underhand practices.
Ms Mowlam responded by saying: "Having read the stories in the Sunday papers, particularly the piece by Ken Follett, I believe there is no-one briefing against me, no foundation to the stories, and I urge Labour supporters simply not to believe the rubbish being peddled."
She added she was looking forward to the party returning "to policy discussions which affect people's lives."
Harsh criticism
But Mr Follett, who is married to Labour MP Barbara Follett, seems intent on stepping up his campaign of open criticism.
On BBC 1's Breakfast with Frost, he pointed to articles in Sunday's papers branding Ms Mowlam
"unreliable".
He claimed Mr Blair was "totally responsible" for the briefings adding: "He
is the only person who can stop it."
The novelist, who has always been known as a strong supporter of Blair, dubbed Alastair Campbell and Peter Mandelson as Tweedle-dum and Tweedle-dee.
"If it is not Alastair, it is Peter Mandelson. They are Tweedle-dum and Tweedle-dee, and if it is not one of those it is somebody who works for them," he said.
"But they all work for the same boss ... it is Tony Blair. If Tony told them to shut up, they would shut up."
Spin doctor responds
But Mr Campbell hit back at the remarks, saying serious people would treat Mr Follett's "rant" with derision.
He said there was not a shred of evidence to the claim that anybody remotely connected with the prime minister had briefed against Ms Mowlam.
"Anyone listening to the interview this morning might be inclined to wonder whether he has a new book coming out in the near future and his publisher's spin doctors are no doubt welcoming all the publicity," he said.