Avigdor Lieberman confirmed on Saturday that he would run in next month's Israeli election, despite a corruption charge that prompted him to resign from the post of foreign minister.

Authorities have said Lieberman will be charged over alleged irregularities in the promotion of an Israeli diplomat who leaked information to him about a police investigation into his activities.

"He is only resigning his post as foreign minister and deputy prime minister, but not as chair of Yisrael Beiteinu or number two on the Likud Beiteinu list," Lieberman's spokesperson Ashley Perry said.

Lieberman's right-wing party Yisrael Beiteinu (Our Home is Israel) and Prime Minister Benjamin Netanyahu's Likud merged into one list ahead of the 22 January poll to form Likud Beiteinu, which opinion polls have predicted will win the election.

Lieberman is second on the party list after Netanyahu and, before his indictment, was widely expected to retain a top cabinet position if the alliance won the election.

A conviction could disqualify him from serving as a minister, but the law does not prohibit Lieberman from running in the election.

On his Facebook page, Lieberman wrote that he hoped his case would be settled before the vote and that he would return to public office.

It is highly unlikely a trial could be concluded in little over a month and some commentators have said he might seek a swift plea deal instead.

An aide to Lieberman said he would hand in his letter resigning as foreign minister on Sunday, and that it would take effect 48 hours later.