Addressing the annual Herzliya security conference on Wednesday, Netanyahu said: "In the end of the day there will be no choice but to remove the Iranian threat in Gaza.
"There will be no escape from toppling the Hamas regime which is the Iranian proxy in the Gaza Strip," he said. "This is the real threat we are facing.
"If I'm elected, the biggest, most important task of my government will be to fend off the Iranian threat in all aspects," he said.
"It will oblige us to work on all fronts, including harnessing the US administration to stop the threat."
The 59-year-old leader of the Likud party, which is expected to have the most seats in the 120-member parliament after next Tuesday's vote, said the divided Palestinians were too weak for a peace deal.
"Palestinian society is deeply divided. They are not strong enough to accept minimal concessions for a peace deal and are not strong enough to fight terror," he said.
"The reality is very clear, any territory we evacuate today will be taken over by Iran," he said, alluding to Israel's withdrawal from Gaza in 2005, which he opposed.
Netanyahu vowed to form a unity government if he wins the elections.
"If elected, I intend to unite all central powers in the country in a national unity government," he said.
"I will turn to our natural allies, but that is not enough. We must unite the entire nation and I will turn to all Zionist parties because, in the face of Iran, Hezbollah and Hamas, the social and economic challenges, we will have to stand together."

Israeli election front runner Benjamin Netanyahu says his first mission if elected prime minister would be to 'thwart the Iranian threat'.
In an interview with Israel's Channel 2 TV late Saturday, Netanyahu said he fully intends to sabotage Tehran's nuclear efforts once and for all.
"Iran will not be armed with a nuclear weapon. It includes everything that is necessary to make this statement come true," said Israel's leading candidate for prime minister.
Israel, the sole nuclear power in the Middle East, accuses Tehran of seeking nuclear weaponry while the UN nuclear watchdog, in its Sept. 15 report on Iran, declared that it could not find any "components of a nuclear weapon" or "related nuclear physics studies" in the country.
Netanyahu, who is currently facing war crime charges in Gaza, claimed the Islamic Republic's uranium enrichment is the greatest danger to Israel and humanity.
After weeks of denying that it used illegal weapons in the densely-populated Gaza Strip, the Israeli military finally admitted Friday that it had pounded the Palestinian coast with at least twenty white phosphorus bombs.
The 1980 third Convention on Conventional Weapons has banned the use of white phosphorus as a weapon, even against military targets situated within population centers.
International attorneys have filed war crime charges against 15 Israeli political and military officials, including Ehud Olmert, Tzipi Livni and Ehud Barak.
Source: Persian News