Boris Johnson believes a "completely crazy" trade boycott against Israel lacks support - with only a "few lefty academics" pursuing the cause.
The London mayor questioned the logic of shunning the Middle East's one "functioning democracy" as he kicked-off a three-day trade mission in Israel and the Palestinian territories.
He wants Israeli companies to return his confidence in their economy by treating London as their first priority when expanding outside of Israel.
Ongoing violence in the region has seen several knife attacks against Israelis and a number of Palestinians shot dead by Israeli security forces.
UK MPs have previously condemned the "terror attacks" on Israel's citizens and aggression against Palestinians.
Speaking during a visit to Tel Aviv, Mr Johnson told reporters: "(A trade boycott) would be completely crazy.
"Why would you - of all the countries in the region, why would you boycott the one which is actually a functioning democracy and a pluralist, open society and all the rest of it?"
The Conservative MP added: "I think the movement for a boycott is not very well supported. A few lefty academics probably."
Mr Johnson's remarks came before he delivered a similar show of support before an audience of around 300 people in Tel Aviv, which included senior Israeli politicians, business figures and British expats.
In 1917, British foreign secretary Arthur Balfour promised the Zionists a homeland in Palestine - known as the Balfour declaration.
And Mr Johnson, who worked on an Israeli communal settlement - a kibbutz - in his early 20s, said: "Whatever the criticisms of Israel may be, some of them justified, some of them less so, and even if it is a tragic fact that the Balfour declaration has been more fulfilled in the protasis than in the apodosi ... i.e. more in the first clause than in the saving clause - it is still the case the first clause of that declaration was a wonderful thing.
"And it's still the case that Israel is the only or by far the most democratic country in the region, the only free country and in my view the only pluralist society.
"And that is why I believe so fervently in this country and that is why I reject completely the suggestion by some corduroy, jacketed, snaggletoothed, lefty academics in the UK.
"By the way, I have nothing against corduroy jackets or indeed snaggleteeth before I get totally massacred by the media.
"That is why I completely reject the suggestion that of all the countries in the Middle East ... that this one, which is free and open and democratic, should be the subject of a boycott."
One woman watching the speech could be heard saying "hallelujah" when this comment was made.
Mr Johnson wants to build London's trading links with Israel - particularly with technology businesses.
He toured Tel Aviv earlier in the day and wore two sets of virtual reality goggles - one which fooled him into believing he was seeing the world through the eyes of a cat before he later realised he was a virtual dog.
Mr Johnson has arrived in Jerusalem for the second leg of his tour, which includes visiting the Palestinian city of Ramallah.
His trip is likely to be regarded as not only an attempt to boost London's standing on the global stage but his own too, ahead of a future Tory leadership contest.