He also attempted to organize meetings of Israeli figures with Iranian spies, presenting the latter as businessmen, the intelligence agency said.
Israel has indicted a former cabinet minister on suspicion of spying for Iran, Israel's Shin Bet internal security service said on Monday.
Israeli police said Segev was arrested last month on his return to Israel after being refused entry to the West African state of Equatorial Guinea because of his criminal record.
The former minister and parliamentarian is alleged to have provided details of Israel's energy industry and security sites in the country, as well as information on political and military officials.
Israel has always been locked in a shadow war with arch-foe Iran, which supports Islamist guerrillas in the Gaza Strip and Lebanon and whose nuclear programme is widely believed to have been targeted repeatedly by Israeli saboteurs.
By going to work for the Iranians, he was reportedly hoping to mislead them and ultimately restore his reputation that was tarnished by the drug bust from over a decade ago, the TV report said.More news: Midges annoy players from England and Tunisia in Volgograd
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According to Hebrew-language media reports, Segev during his interrogation told investigators that he had no ideological or financial motive in helping Iran, and that he did not hand over any classified information.
In January, Israel said it had cracked a Palestinian militant cell suspected of having been recruited and handled by Iranian intelligence officers who worked out of South Africa.
According to Israel, Segev maintained contacts with Israeli citizens in the defense and security sectors, as well as with Israeli diplomats in order to obtain information. More recently, Israeli forces have carried out a number of airstrikes on Iranian forces in neighboring Syria.
Segev is reportedly now being held at a Shin Bet facility.
In a statement, Shin Bet said the Jerusalem District Prosecutor's Office submitted charges against Segev on Friday accusing him of aiding an enemy country, spying against Israel, and passing multiple messages to an enemy. All further information on the case remains under a court-imposed gag order.
"Even at this early stage it can be said that the permitted publication attributes extreme gravity to the events, even though within the indictment, of which the full details remain confidential, a different picture is painted", the lawyers stated.