An Israeli official accompanying Israeli Prime Minister Ehud Olmert on a visit to Moscow declined to comment on the report. Olmert flew to Moscow to press Russia not to sell advanced missiles and weapons technology to Iran and Syria.
The report on Channel 10 said any strike against Iran would leave U.S. forces based in Iraq vulnerable to retaliation. Depending on who becomes the next U.S. president, troops could remain in Iraq from under two years to indefinitely.
If elected, Barack Obama wants to remove U.S. combat troops within 16 months of taking office in January 2009. John McCain, a staunch supporter of the Iraq war, has refused to provide a timetable and says troops could remain there indefinitely.
Channel 10 added that because Israel was starting to realise that international efforts and United Nations sanctions aimed at halting the Islamic Republic's nuclear programme would fail, Israel understood it would one day have to face a nuclear Iran.
The West accuses Iran of covertly developing nuclear weapons under cover of a civilian programme. Tehran says says it seeks nuclear technology solely for power generation.
The report said that officials at Tzipi Livni's foreign ministry were working on policy papers to prepare for a nuclear Iran.
Livni has been nominated to form a new coalition government and if successful she will take over as prime minister from Olmert who resigned last month in a corruption scandal. Olmert remains caretaker premier until a new government is formed.
Though apparently inconclusive on other matters, Olmert's talks in Moscow with Russian Foreign Minister Sergei Lavrov found some common ground on the issue of halting Iran's uraniam enrichment programme, an Israeli official told reporters.
Tehran last month rejected a United Nations Security Council resolution demanding it halt its enrichment work.
Israel, widely believed to be the Middle East's only nuclear power, sees Iran's nuclear programme as a security threat, citing remarks by President Mahmoud Ahmadinejad calling for the Jewish state's demise.
(Additional reporting by Allyn Fisher-Ilan in Moscow)
