Opposition leader and Zionist Union head Isaac Herzog is one of the two Israeli politicians probed by the police for suspected wrongdoing in two unrelated cases, officials said on Wednesday.

The second politician being examined by the Israel Police fraud squad is Interior Minister Arye Dery.

With regard to Herzog, police are looking into suspicions he received financial contributions from an interested party for political activity during the Labor Party's 2013 primary election.

Haaretz reported on Tuesday evening that in addition to Dery, police were looking into suspicions that a senior politician, now identified as Herzog, received funding for political activities from interest groups.

Attorney General Avihai Mandelblit notified Herzog on Wednesday that the Justice Ministry intends to put out an official statement about the police probe into his affairs, following the exposure of the case by Haaretz.

The ministry confirmed that "with the permission of the attorney general an examination has been opened into matters related to the opposition chairman's conduct in the recent Labor Party primaries.

"At this stage the attorney general has not given any instructions to open an investigation against the opposition chairman," the ministry added.

Testimony has been taken from several figures against Herzog in an examination launched after a complaint of alleged criminal wrongdoing was made against Herzog's people in the 2013 primaries.

Text messages and receipts that may support the complaints have been seized.

Herzog said he welcomes the probe but asserted it stems from "political slander that Likud and frustrated activists tried to disseminate before the elections, and was denied at the time."

"I'm sure the probe will disprove these strange claims once and for all," he said, adding that he will cooperate with the examination fully.

Though both cases have been under investigation for the last few months, both are still at a relatively early stage. So far, neither politician has been questioned under caution.

Zionist Union MK Micki Rosenthal said "the guiding principle in such cases must be one rule for all – for senior politicians to be treated the same as any other person. Every suspicion must be fully investigated and every elected official must cooperate with law enforcement. There is no such thing as an investigation for the privileged."

Rosenthal also said that any public official who is charged ought to resign from his post.

Former Labour chairwoman, Shelly Yechimovitch, tweeted that she didn’t know the details yet and was therefore not planning to comment.

Likud Youth Movement chairman David Shayan urged police to widen the investigation, suggesting he thought the probe was due to a complaint he made against Herzog more than a year ago.

"Now the truth is coming to light about Herzog and his ways," Shayan wrote on his Facebook page.