US Secretary of State John Kerry admitted on Thursday there was scepticism and cynicism about his bid to broker new talks between Israelis and Palestinians on his fourth visit to the region.

Flying in from a night of diplomacy in Amman over the war in Syria, Kerry went straight into talks with Prime Minister Benjamin Netanyahu before travelling to the West Bank to meet Palestinian president Mahmud Abbas.

Kerry has now visited Israel as many times in his first months in office as his predecessor Hillary Clinton did in four years as top US diplomat. And in a rare show of support for the Palestinians, he did a brief walkabout in Ramallah.

Despite public pronouncements of support, there is a growing frustration that there has been little sign of a shift in the long-held positions of both sides.

Complicating efforts is the new Israeli government, which has moved more towards the right and includes some ministers who oppose a two-state solution.

"There are ideological differences at the heart of the government," said Justice Minister Tzipi Livni, who is also Israel's top peace negotiator.

The lack of talks "only serves the interests of those who think that each passing day (without a peace agreement) allows them to build a new house," she told public radio, referring to Jewish settlement building.

But after Kerry and Netanyahu talked for some two hours -- half of it alone -- Livni said time was of the essence.

"Let's put the blame game aside and let's enter the negotiations room the sooner the better. The next days and weeks are critical, and it's important everyone stays focused," she said in a statement.

Kerry, who last week was the subject of a scathing portrait in the Israeli daily Haaretz which called him "a naive and ham-handed diplomat who has been acting like a bull in the china shop," acknowledged the difficulties ahead.

"I know this region well enough to know there is scepticism, in some quarters there is cynicism and there are reasons for it. There have been bitter years of disappointment," he said.

But he insisted: "It is our hope that by being methodical, careful, patient, but detailed and tenacious, that we can lay on a path ahead that can conceivably surprise people and certainly exhaust the possibilities for peace."

Kerry then went to Ramallah to meet with Abbas -- also for more than two hours and again the two men held a long tete-a-tete.

The US diplomat "provided a detailed update on ideas to strengthen the Palestinian economy the Quartet has been working on with members of the private sector," a State Department official said, asking not to be named.

And in a powerful message to Palestinians who are used to just seeing American motorcades sweep by into Abbas's high-walled headquarters compound, Kerry went for a stroll along a Ramallah street.

Under the watchful eye of his security men, he stopped at the popular Samer's restaurant for a turkey shawarma sandwich, and then walked across the street to the restaurant's sweet shop to sample traditional Palestinian sweetmeats.

Sipping a strong Arabic coffee, Kerry discussed peace with the owner, who said in English: "We hope for a peaceful country with all these attacks around us" and thanked him for visiting the West Bank.

British Foreign Secretary William Hague, also visiting Israel, backed Kerry's efforts.

"The Middle East peace process is... an urgent priority for the United Kingdom and to the world," he said.

"We urge all parties to move the process forward and to really give the bold and decisive leadership that will allow success."

Kerry also revealed that US General John Allen, the former commander of US and NATO forces in Afghanistan, was "here on the ground working with his counterparts on the issues of security".

Allen, who declined a post to become the NATO supreme allied commander in Europe, is tipped to become a special US security coordinator to Israel.

After whirlwind talks on Thursday and Friday, Kerry will return to the region on Sunday to attend the World Economic Forum in Amman.

Abbas has also been invited to the forum, and it is possible Kerry could unveil then his plans for the economic revival of the occupied West Bank.