One hundred and forty-five lawmakers out of 217 voted to pass the 36-article law, which criminalises any retribution against whistleblowers including any disciplinary measures against civil servants.
“Strong legislation like this helps fight corruption,” said Civil Service Minister Abid Briki, who attended the session.
The parliament’s deputy speaker Abelfattah Mourou said the law was “a gain from the revolution”.
At least 450 million dinars ($230m) in bribes were slipped to state employees in 2013 alone, says the Tunisian Association for Public Auditors.
Prime Minister Youssef Chahed’s government has made corruption a priority since taking office last year, when the head of the national anti-graft body Chawki Tabib warned graft had reached “epidemic” proportions.
Corruption was widespread under Ben Ali, whose close circle – especially his wife’s family – had an iron grip on the economy.
Tunisia was ranked 75th out of more than 170 countries in the 2016 corruption perceptions index published by Transparency International. It had been 59th in 2010.
The anti-graft body honoured 10 whistleblowers in corruption cases last month in a move to encourage more people to come forward.