The head of the parliamentary Committee on Public Enterprises, or COPE, Wijeyadasa Rajapakshe, said the state will try to recover at least some of the money.
"We plan to seek legal redress over the privatisation deals," Rajapakshe told AFP.
COPE, which last year probed 26 of the 210 state enterprises, found fault with Sri Lanka's Central Bank too for not monitoring financial institutions properly and failing to recover large amounts due to the state.
"As a result of these inefficiencies and corrupt deals, we estimate Sri Lanka may have lost in excess of 100 billion rupees (one billion dollars) last year alone," said Rajapakshe, who is also a ruling party law-maker.
The loss is about a fifth of government revenue and around four percent of the 24-billion dollar economy.
He said sections of public interest groups were also looking at filing separate civil action against heads of state enterprises who have squandered millions of dollars.
In his investigations, Rajapakshe discovere