SYDNEY - Since taking over as Prime Minister in August, Mr Scott Morrison has presented himself as a no-nonsense leader focused on the everyday interests of ordinary Australians.

So it was surprising to see him call a sudden press conference this week to float the possibility of following United States President Donald Trump's controversial decision to recognise Jerusalem as the capital of Israel.

Mr Morrison's move was criticised by commentators, while Indonesia, a Muslim-majority nation, expressed strong concern over his announcement.

Indonesia, which has at times had strained ties with Australia, reiterated its position that the status of Jerusalem must be negotiated as part of a two-state solution in the Middle East dispute between the Palestinians and Israel.

Analysts said the announcement could jeopardise a proposed free trade agreement with Indonesia and would put pressure on President Joko Widodo, who faces an election next year, to publicly rebuke Australia.

But this seemingly unusual decision by Mr Morrison to wade into Middle Eastern politics yet again proves the adage that all politics is local.

His announcement came just days ahead of a crucial by-election on Saturday in a Sydney seat with a sizeable Jewish vote. A loss for Mr Morrison in Wentworth would cost the ruling coalition its razor-thin Parliamentary majority.

It would also place immense political pressure on Mr Morrison, whose Liberal party, or its conservative predecessors, have never lost the seat.

But it soon became clear why Mr Morrison may be resorting to measures that appear so politically desperate.

It emerged on Wednesday (Oct 17) that internal opinion surveys by the Liberal party suggest that its candidate Dave Sharma, a former Australian ambassador to Israel, is at risk of losing in Wentworth.

According to a survey conducted by the Liberal party, published in The Australian, Mr Sharma trails independent candidate Kerryn Phelps, a prominent doctor, 45 per cent to 55 per cent. The survey also found that 75 per cent of people in the seat believe that Mr Sharma will win.

These survey results pose a dilemma for the Liberal party, which fears that some of its supporters will vote for Ms Phelps as a "protest vote" in the belief that she would not actually win.

Such a protest would be motivated by anger over the treatment of the popular former Wentworth MP Malcolm Turnbull, the ex-prime minister who quit Parliament after being ousted by his party as leader. It was Mr Turnbull's resignation that prompted the by-election.

All of this explains Mr Morrison's sudden foray into the Israeli-Palestinian conflict. He said he would consider moving Australia's embassy from Tel Aviv to Jerusalem and also announced a review of the Iran nuclear deal, which Australia has so far supported despite Mr Trump pulling out of it.

Mr Morrison is trying to appeal to the Jewish population in Wentworth, which accounts for about 12 per cent of voters.

Political commentator Peter Hartcher said Mr Morrison was risking Australia's relations with Indonesia, including his personal relations with Mr Joko and cooperation on counter-terrorism and border security.

"This is unprincipled and craven politics of a low order," Mr Hartcher wrote in The Sydney Morning Herald. "He must know how much he could be putting at risk. That's why he's only flirting with these ideas, not actually embracing them."

Mr Tony Walker, a former Middle East correspondent who is now a Vice-Chancellor's Fellow at La Trobe University, said Australia should support a push for compromise in the Middle East rather than "auctioning its foreign policy to the highest bidder - in this case, the voters of Wentworth".

"There is no advantage for Australia in turning Middle East policy on its head beyond domestic considerations," he wrote on The Conversation website yesterday.

Defending the move on Wednesday, Mr Morrison said he and Foreign Minister Marise Payne had been in contact "throughout the day" with their Indonesian counterparts, Mr Joko and Ms Retno Marsudi, to discuss his new Middle East stance.

"You've got to just stand up for what you believe and you can do that when you've got good relationships with your neighbours, which we do," he said.

The Liberals may yet win Saturday's by-election, as they are expected to do. But Mr Morrison will face a general election, due early next year, in which he could face the consequences of a short-term move aimed squarely at a single seat.