Weightlifters Edwin Raju and Tejinder Singh were banned for life by the Indian Weightlifting Federation on Sunday.
Raju finished fourth in men's 56 kg division competition, in which compatriot Vicky Batta won the silver medal.
Tejinder pulled out of the men's 85 kg class competition at the last minute, citing "illness".
Women lifters Shailaja Pujari and B Prameelavalli were also handed two-year suspensions.
Prameelavalli, who dropped out of the Melbourne-bound weightlifting team at the last minute, and Shailaja tested positive for a banned substance after a random test by the World Anti-doping Agency during a preparatory camp in Patiala.
The positive tests resulted in the Indian Weightlifting Federation being banned by the ruling body for the sport for the second time in seven months after coming out of a year's suspension.
All the four lifters were found to have traces of stanozonol, a banned steroid, in their samples.
Raju and Tejinder will also have to pay a fine of Rs 10,000 each, the IWF announced after its Executive Committee Meeting on Sunday.
"The ban will come into effect after the verdict of Court of Arbitration for Sports which is hearing their case," IWF president H J Dora said.
"The decision was taken in accordance with the anti-doping rules adopted by the national body in September 2004," he added.