The axe on Zaichkov and Kachan came down two days after Lukashenko, who also serves as president of the Belarus Olympic committee, blamed them for the country's "complete failure" in London.
"Belarus people will no longer tolerate such a disastrous showing. I think those who are responsible for our performance in London should resign," Lukashenko told delegates at the annual BOC convention.
"The performance of our Olympic team in Britain this summer was a complete failure," he said, referring to a total of 12 medals, two of them gold.
"Only 12 medals out of the 25 that you had promised us - it is a noticeable step back compared to what we had achieved (at the 2008 Olympics) in Beijing."
Belarus ended up 26th in the overall Olympic medal standings in London after shot putter Nadezhda Ostapchuk was stripped of her gold after testing positive for a banned anabolic steroid.
Ostapchuk, 31, was handed a one-year ban by the Belarus anti-doping agency last month.
In Beijing, the former Soviet state had their largest-ever medal haul - winning 19, four of them gold.
Lukashenko has been alienated by the West who have punished his lack of tolerance for dissent with sanctions.