He displayed a sign saying 'RIP Fergie' during the open-top bus parade through Manchester to celebrate City's Barclays Premier League title win on Monday. City expressed "sincerest apologies" and said Tevez had made a "significant error of judgement". A Tevez statement said he got "carried away in the excitement of the moment".
But in comments carried by Argentinian website www.ole.com.ar, Tevez said: "It seems like Ferguson is the president of England. Every time he speaks badly about a player or says terrible things about me, nobody says that he has to apologise. [But] when someone comes out with a joke or banter, you have to say sorry - but I don't say sorry."
The placard, passed to Tevez by a fan, is thought to have been a reference to a remark by Ferguson three years ago when asked if United would ever be underdogs against City. "Not in my lifetime," said the Scot.
Tevez was quizzed about the incident on arriving back in his native Argentina for his summer break. He played under Ferguson for two years at Old Trafford before leaving for City in 2009.
In March Ferguson suggested City were desperate in recalling Tevez, 28, following the forward's infamous stand-off with the club, which saw him spend more than three months in Argentina on unauthorised leave.
Ferguson was responding to remarks by City's football development executive Patrick Vieira, who said Paul Scholes' return from retirement for United seemed a sign of weakness.
Tevez's return to the City side for the title run-in provided them with a much-needed spark in their fight against United. He scored four goals, including one hat-trick, and started the last five games as City overhauled an eight-point deficit to finish ahead of United on goal difference.
Midfielder Gareth Barry said: "When we were eight points behind, it all turned on that win over West Brom. Carlos had come back and that lifted everyone - he was working really hard, and started in that game."
City had no comment when contacted about Tevez's comments.