"If not now then when?" the official quoted Netanyahu as saying. He spoke on condition of anonymity because he was not allowed to speak with the media.
He did not disclose what kind of action Netanyahu recommend be taken.
Iran kept the facility, located 100 miles southwest of Tehran, hidden from the U.N. nuclear watchdog until revealing it last week.
Israel has long sounded alarm bells over its belief that Iran is seeking nuclear weapons while Tehran insists its facilities are only for producing nuclear fuel for power plants.
Israeli Foreign Minister Avigdor Lieberman said earlier Saturday that the Iranian nuclear facility proves "without a doubt" the Islamic republic is pursuing nuclear weapons.
"This removes the dispute whether Iran is developing military nuclear power or not and therefore the world powers need to draw conclusions," Lieberman told Israel Radio. "Without a doubt it is a reactor for military purposes not peaceful purposes."
The facility enriches uranium fuel to power nuclear reactors. Highly enriched fuel, however, can also be used to make weapons. Evidence of the clandestine facility was presented Friday by President Barack Obama and the leaders of Britain and France at the G-20 economic summit in Pittsburgh.
Obama demanded Iran show greater transparency regarding its nuclear program warning or face tougher sanctions.
Iranian President Mahmoud Ahmadinejad later said his country had done nothing wrong and Obama would regret his actions.
Iran insists its facilities are producing nuclear fuel for power plants and not weapons.
Israel considers Iran a strategic threat due to its nuclear program, missile development and repeated references by Iranian President Mahmoud Ahmadinejad to Israel's destruction.
Israel is widely believed to have a nuclear arsenal of its own.
Lieberman said he met with Arab foreign ministers while at the United Nations last week and said they expressed their alarm over Iran's nuclear program to him.
"Nobody is worried about the Palestinian problem, everybody in the Muslim and Arab world, and first and foremost in the Gulf states, are worried about the Iranian problem," Lieberman said.
