The Met Police chief is under mounting pressure following claims he will be criticised by the official inquiry into the shooting of a Brazilian man.
Sir Ian Blair has been criticised for police action
A leaked copy of the Independent Police Complaints Commission report blames Sir Ian Blair for a "catalogue" of blunders, the News of the World says.
Both the Home Office and the Metropolitan Police have refused to comment on the claims.
The policing minister said Sir Ian was currently "entirely safe" in his job.
The News of the World says it has seen the report into the shooting of Jean Charles de Menezes at Stockwell tube station last July after officers mistook him for a suicide bomber.
It alleges there is evidence some of Sir Ian's senior officers knew Mr Menezes was definitely not a suicide bomber just hours after he was killed - but failed to tell their boss until the next day.
The IPCC said the News of the World's article was not "an accurate or fair description" of its unpublished findings.
The commission is also investigating the recent shooting of a man during a raid on a house in Forest Gate, east London, carried out by 250 officers acting on intelligence that a chemical device was in the house.
Two brothers, Mohammed Abdulkahar and Abul Koyair, were held for a week on suspicion of terrorism involvement but released on Friday without charge.
Policing Minister Tony McNulty said Sir Ian was "entirely safe" for now, but did not speculate on his future or the outcome of the two IPCC investigations.
Mr Menezes was killed after being mistaken for a suicide bomber
"I am not going to speculate on what is in those documents and what consequences there are for any individual. We will have to wait and see," he told BBC Radio 4's The World This Weekend.
"I am, at this stage, saying the Metropolitan commissioner is entirely safe in his job and will not add to the speculation about what might or might not happen to his job in the circumstances of reports we have not even seen yet."
Mr McNulty was reluctant to comment on an Observer article alleging some police had doubts about the intelligence which prompted the Forest Gate raid.
"We do need to fully understand exactly what went on, why it went on, what the provenance of the intelligence was, and all those other matters before people jump to what can only be speculative conclusions at this stage," he said.
The police chief received strong support from London's mayor Ken Livingstone.
"I obviously cannot comment on leaked reports but it is quite clear to me that no-one has done more to build the good community relations which are essential to effective policing than Sir Ian Blair.
"All of our polls show rising confidence in Sir Ian Blair's neighbourhood policing strategy and he continues to have my full confidence."
The IPCC said that it would release the report "as soon as the legal processes permit".
Before the News of the World was published, the IPCC said it applied unsuccessfully for an injunction "to protect the confidentiality" of its report into the death of Mr Menezes.