“If he stays he will be team principal – nothing else – or he will retire”
Lauda, Mercedes’ F1 chairman, said recently he was in talks with the 58-year-old Briton but that a decision will not be made until after the season.
The Austrian great also said he wants Brawn to stay.
But reports on Tuesday suggested Brawn has now definitively decided to step down, in order to be replaced by new team boss Paddy Lowe.
“I hate all this bulls**t,” triple world champion Lauda is quoted on Wednesday by the Daily Mail.
“The (latest) speculation is total rubbish.”
However, F1 chief executive Bernie Ecclestone has hinted that the decision about Brawn has in fact been made.
“I think they have decided that Ross is going, and that seems to be the end of it,” he said.
The Daily Mail said the uncertainty could be because Lauda wants Brawn – a renowned engineer with race and title-winning pedigree at Benetton, Ferrari and his own Brawn GP – to stay, while Toto Wolff wants Lowe to succeed him.
Lauda said: “I am trying everything I can to encourage and motivate him to stay. I want him to do it. But it is not my decision; it is his decision.”
Brawn said recently he will only stay if he can remain team boss, and so Lauda denied suggestions the current talks are about negotiating a lesser role for the 58-year-old Briton.
“If he stays he will be team principal – nothing else – or he will retire,” he said.