"I would not feel comfortable with this (reducing Armstrong's ban) because it is too little, too late. It was not even a real admission," Bach told the AP after addressing delegates at the World Conference on Doping in Sport.
"Now trying to bargain a deal there after everything has been proven, and now that he realizes he doesn't just get off the hook — this is not the best way, to lessen a sanction or to be lenient there in any way," he added.
Bach supported cycling's move toward an open process with regard to its drug-stained past. Cycling and its dark doping history has become a key behind-the-scenes issue at the conference.
Bach told the AP he will meet with Brian Cookson, the new head of cycling governing body UCI, on Wednesday or Thursday in Johannesburg. The UCI has approached the IOC to "consult" on some of its doping issues, Bach said.
"I think cycling is taking the opportunity to strengthen their fight against doping," Bach said. "What I have seen and heard so far is that the UCI is really going in the right direction."
Bach, who was elected to succeed Jacques Rogge in September, voiced his support for doubling the standard suspension for serious doping violations from two years to four.
WADA is expected to approve the move to four-year bans later this week along with other revisions to the international anti-doping code. The new code will come into effect on Jan. 1, 2015, and in time for the Olympics in Rio de Janeiro in 2016.
The four-year bans will ensure doping violators miss at least one Olympics, an important factor for Bach. A previous IOC rule to that effect was thrown out by the Court of Arbitration for Sport because it wasn't included in the WADA code.
"It adds to the deterring factor of the sanction because until now there was something in between, they could still come back at the next edition of the games," Bach said. "And some may even have calculated with this comeback and therefore it is a very important step forward."
Bach said he once supported lifetime bans for a first offense, a move that has been ruled out because of human rights issues. Lawyers advised Bach that lifetime bans for first offenses wouldn't be possible.
"It is a pity but you have to expect this," Bach said.
In his speech to the conference, Bach said the 2014 Winter Olympics in Sochi, Russia, will be the most drug-tested in Winter Games history.
There will be 1,269 pre-competition tests ahead of the games, up from 804 at the 2010 Vancouver Games. There will be a total of 2,453 tests around the games, up from 2,149 four years ago. The IOC will spend $1 million on pre-competition testing for Sochi and "many millions" on testing throughout the Feb. 7-23 games.
"To be clear ... To be very clear. These millions of dollars are not expenses. They are an investment in the future of our sports," Bach said.