"An apology for expression of his beliefs, conditional or unconditional, would be insincere," he said.
Bhushan said as an officer of court he believes it's a duty to speak up when he believes there is a deviation from its sterling record.
"Therefore I expressed myself in good faith, not to malign the Supreme Court or any particular Chief Justice, but to offer constructive criticism so that the court can arrest any drift away from its long-standing role as a guardian of the Constitution and custodian of peoples' rights," he said.
He said: "My tweets represented this bonafide belief that I continue to hold. Public expression of these beliefs was I believe, in line with my higher obligations as a citizen and a loyal officer of this court. Therefore, an apology for expression of these beliefs, conditional or unconditional, would be insincere."
Bhushan further said that an apology cannot be a mere incantation and any apology has to, as the court has itself put it, be sincerely made.
"This is especially so when I have made the statements bonafide and pleaded truths with full details, which have not been dealt with by the Court. If I retract a statement before this court that I otherwise believe to be true or offer an insincere apology that in my eyes would amount to the contempt of my conscience and of an institution that I hold in highest esteem," he said.
On August 20, the top court had granted time till August 24 to Bhushan to reconsider his defiant statement refusing to apologise and tender unconditional apology for contemptuous tweets against the judiciary and rejected his submission that quantum of punishment be decided by another bench.
The apex court, on August 14, had held Bhushan guilty of criminal contempt for his two derogatory tweets against the judiciary saying they cannot be said to be a fair criticism of the functioning of the judiciary made in the public interest.
He faces simple imprisonment of up to six months or with a fine of up to Rs 2,000 or with both as punishment.