Zulfiya Chinshanlo, Maiya Maneza and Svetlana Podobedova were all caught when samples from 2012 and the 2008 Games in Beijing were retested.
Chinshanlo won at -53kg, Maneza at -63kg and Podobedova at -75kg and all tested positive for steroid stanozolol.
It has not been confirmed if their golds will now be re-assigned.
Eight athletes were sanctioned on Thursday, with Marina Shkermankova of Belarus losing her London 2012 bronze medal in the -69kg class.
All Kazakh and Belarusian weightlifters could now be banned for a year from all international weightlifting competitions.
Under International Weightlifting Federation rules, automatic bans come into effect if at least three of a country's athletes fail Olympic retests.
The International Olympic Committee has reported a total of 98 positive cases from recent retests of samples from the Beijing and London Games.
At least six of those cases came in one weightlifting event, the men's -94kg category in 2012.
Three weightlifters from Kazakhstan have been stripped of Olympic gold medals won at London 2012 after new tests found them guilty of doping.