Israel and its US ally have hit a troubled patch in their close relationship, caused by differences over Iran's nuclear plans and peace with the Palestinians.

In a highly public spat, Israeli Prime Minister Benjamin Netanyahu and President Barack Obama are each seeking to directly address the other's public.

At the moment, Israeli Economy Minister Naftali Bennett is campaigning in Washington, while the US ambassador to Israel, Dan Shapiro, has been making his case in the Israeli media.

"I'm not telling the Americans what they should do; I just give them the information, it's for them to decide," Bennet, who heads the far-right Jewish Home party, told Israeli public radio by telephone on Friday.

"It's not really lobbying, more a dialogue between friends," he said of his meetings on Capitol Hill and a speech to the Brookings Saban Center for Middle East Policy.

Meanwhile, Shapiro told public radio the high-profile war of words over a nascent deal Western powers are negotiating with Iran, which would see some easing of sanctions against the Islamic republic, was regrettable.

"It would be preferable if our differences were addressed in private, but sometimes that's not possible," he said.

In a speech to North American Jewish leaders in Jerusalem this week he said Obama "has made it crystal clear that he will not permit Iran to acquire a nuclear weapon, period, and is prepared to use all elements of our national power to ensure that we are successful."

Despite such reassurances, Israeli media speak of a trans-Atlantic crisis of confidence over what Israel and the US say are Iran's plans to develop a nuclear weapon. A second element involves increasingly fragile peace talks with the Palestinians amid an Israeli West Bank settlement drive, which has come in for sharp US criticism.

On Friday, left-leaning daily Haaretz cited an unnamed senior Israeli minister saying that Secretary of State John Kerry "can no longer serve as an honest broker between Israel and the Palestinians".

Israeli Home Front Minister Gilad Erdan lashed out at Kerry on Thursday for slamming Netanyahu's intensive campaigning against the emerging nuclear deal with Iran.

"I was astounded to hear John Kerry's remarks about why the prime minister is criticising the agreement being formulated in Geneva without waiting for it to be signed," Erdan told an Institute for National Security Studies conference in Tel Aviv.

"When we're dealing with a country that wants to destroy Israel and the conditions that will enable it to carry out its wishes, what do they expect from the Israeli prime minister? Not to cry out when they're holding the knife, but only when it's at our throat?" he asked.

On Monday, Kerry had said Washington had Israel's interests at heart and that he shared Netanyahu's "deep concerns" about Iran.

"But I believe the prime minister needs to recognise that no agreement has been reached about the endgame here that's the subject of the negotiations," he said.

A 'bad and dangerous' deal

Netanyahu has repeatedly warned world powers against striking a "bad and dangerous" deal with Iran that fails to bring its alleged military nuclear programme to a complete halt.

On Wednesday, he warned that a "bad deal" could result in war.

Israel, the region's sole if undeclared nuclear power, views a nuclear Iran as an existential threat and has said it will not be bound by any deal with its arch-foe, refusing to rule out military action to halt its programme.

Netanyahu's hard line has the backing of the Israeli public, according to an opinion poll published on Friday that showed 65.5 percent of Jewish respondents opposed to a deal with Iran.

President Shimon Peres, however, urged restraint in relations with Washington.

"There can be disagreements, but they must be conducted with a view to the true depth of the situation," he said in a speech on Thursday night.

"If we have disagreements we should voice them, " he said. "But we should remember that the Americans also know a thing or two; we are not the only ones."

Public radio commentator Ronen Pollak said Netanyahu knows that a deal with Iran is inevitable, "but he has decided on a trial of strength with Washington so that the agreement is the least bad possible."