A Tunisian allegedly caught red-handed taking a bribe was among three regional officials sacked on Monday by Prime Minister Youssef Chahed, who has vowed to fight graft.

A government statement announced the sackings but did not say why the three were relieved of their duties.

An official source later told AFP that two of the dismissals were "disciplinary" cases and confirmed that the third was sacked for "being caught red-handed for corruption".

A spokesman for a provincial prosecutor said one of the officials had been arrested during a police sting allegedly pocketing money from a businessman who had complained to authorities that he had been asked to pay bribes.

According to spokesman Mohamed Ali Barhoumi, the businessman told authorities the official pestered him with demands for a payment for the renewal of the lease for his shop.

The suspect allegedly pocketed 500 dinars (around 200 euros/dollars) from the shop-owner in the police operation, Barhoumi said.

Corruption was widespread under longtime president Zine El Abidine Ben Ali, who was ousted in a 2011 uprising, and has remained endemic since.

Chahed's government has made fighting corruption a priority since taking office last year, when the head of the national anti-graft body Chawki Tabib warned the problem had reached "epidemic" proportions.

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.

In January, the anti-graft body honoured 10 whistleblowers in corruption cases in a move to encourage more people to come forward.