Gonen Segev, energy minister from 1995 to 1996, made contact with Iranian officials at the Iranian embassy in Nigeria in 2012 and he also visited Iran twice for meetings with his handlers.
An Israeli former cabinet minister admitting to spying for Iran on Wednesday in a plea deal in exchange for an 11-year prison sentence, the Israeli Justice Ministry said.
Gonen Segev, energy minister from 1995 to 1996, was indicted in June. The Shin Bet internal security service said at the time had been recruited by Iranian intelligence while living in Nigeria and had "served as an agent".
Investigators found that Segev made contact with officials at the Iranian embassy in Nigeria in 2012 and that he visited Iran twice for meetings with his handlers, the Shin Bet said.
Segev, it said, received an encrypted communications system from Iranian agents and supplied Iran with "information related to the energy sector, security sites in Israel and officials in political and security institutions".
Israel has long been locked in a shadow war with Iran, which supports anti-Israeli groups in the Gaza Strip and Lebanon. Iran has accused Israel of being behind acts of sabotage and assassinations of scientists involved in its nuclear programme.
The court has yet to formally approve the prison sentence agreed with Segev, a physician, who had been jailed in 2004 for attempting to smuggle "Ecstasy" pills into Israel and left the country in 2007 after his release from prison.
He was arrested in May during a visit to Equatorial Guinea and extradited to Israel, Shin Bet said.
There was no immediate response from Iran to the Justice Ministry statement.