Sharon made the comments during talks with a visiting delegation from the US Congress, despite months of press reports to the contrary, the official said in Jerusalem on Tuesday.
"Israel has no intention of attacking Iran and continues to support the diplomatic efforts of the international community, in particular the United States, to stop Iran from acquiring nuclear weapons," he quoted Sharon as saying.
Earlier this month, Britain's Sunday Times reported that Israel had drawn up plans for a combined air and ground attack on Iranian nuclear sites should diplomatic efforts fail to halt Tehran's alleged nuclear programme.
Sharon's inner cabinet gave "initial authorisation" for an attack at a private meeting in February on his ranch in the Negev desert, the weekly said.
US Secretary of State Condoleezza Rice said immediately that Washington had not sanctioned any Israeli military strike against Iranian nuclear sites.
"Israel has no intention of attacking Iran and continues to support the diplomatic efforts of the international community ..."
Britain, France and Germany have been trying to secure guarantees that Iran will not seek to acquire nuclear weapons in exchange for a plethora of trade, security, diplomatic and technology agreements.
The United States and Israel accuse Iran of seeking to develop nuclear weapons. Washington has not ruled out military options to prevent Tehran from acquiring the bomb should diplomacy fail.
Ideally, the Europeans would like to see Iran call a permanent halt to its uranium enrichment activities, which are currently suspended.
Iran maintains it has the right to enrich uranium to produce atomic fuel, but once mastered the fuel cycle can be diverted for military purposes. Iran says it has no intention of doing that.