Israeli authorities are investigating Interior Minister Aryeh Deri for alleged corruption, local media said Wednesday of the ultra-Orthodox party leader who has already served prison time for graft.

Deri confirmed on his Twitter account that he was under investigation, saying he had requested that a gag order on the publication of his name be lifted and that he was ready to "respond to all questions."

News of the investigation into an unnamed senior politician first emerged late Tuesday in a report by Channel 2 television.

A second unidentified senior politician was also said to be under investigation. No details of the probes were made public, including when the alleged wrongdoing took place.

Deri, head of Sephardi ultra-Orthodox party Shas, became interior minister in January after the resignation of Silvan Shalom following allegations of sexual harassment.

Shas is vital to Prime Minister Benjamin Netanyahu's right-wing governing coalition, which holds a one-seat majority in parliament.

Deri, who had served as interior minister from 1988 to 1993, was sentenced to three years in prison in 2000 for taking $155,000 in bribes, though his sentence was reduced by a third for good behaviour.

Deri resigned as economy minister in November after refusing to overrule anti-trust authorities' objections to a major natural gas deal being pushed by Netanyahu.

His resignation allowed Netanyahu to take over the economy minister post himself and move ahead on the gas deal.

In January, critics of his appointment as interior minister said the post should not be granted to someone who had been convicted for corruption. Others argued that Deri had paid his debt to society.

The interior ministry notably oversees local government and efforts to prevent illegal immigration. The police fall under a separate ministry.