The announcement is the closest New Delhi has come to abandoning the long-delayed engine programme, which has suffered from major performance issues and cost overruns.
Antony noted that the Tejas requires an engine capable of producing 90kN (20,200lb) of thrust, but the "Kaveri does not fully meet this requirement."
"Therefore, it has been decided to use variants of Kaveri engine to power unmanned air vehicles and also for marine applications," he says.
He adds, however, that a Kaveri jet engine could be tested aboard a Tejas Mk 1 in another three years. This suggests that major issues still need to be ironed out before the engine is married to a manned fighter.
Antony made the comments in a written reply to a question in parliament.
The Tejas Mk I uses the General Electric F404 power plant, while the planned Tejas Mk II will use the General Electric F414.
In March, Antony told parliament that the Kaveri's development cost was Rs28.39 billion ($528 million), nearly 10 times greater than the Rs3.83 billion originally allocated.