Australia’s spy agency warned ministers that Scott Morrison’s proposed shift in Middle East policy to relocate the embassy in Israel from Tel Aviv to Jerusalem may “provoke protest, unrest and possibly some violence in Gaza and the West Bank”.

Guardian Australia has obtained an Asio bulletin, marked secret, AUSTEO (Australian eyes only), circulated on 15 October – the day before Morrison’s announcement – that notes that the putative shift would “attract international attention”.

“We expect any announcement on the possible relocation of the Australian embassy to Jerusalem or consideration of voting against Palestinians in the United Nations may provoke protest, unrest and possibly some violence in Gaza and the West Bank,” the bulletin says.

Asio bulletin marked secret about the possible relocation of Australia’s embassy in Israel

It warns it is possible Australian interests could be the target of protest activity following any public announcement by the government, and notes “attacks and violent protests” have occurred at times of heightened political tension.

It notes that Australian diplomatic facilities in Iran could also be the focus of protest activity if the Morrison government withdrew from the Iran nuclear deal – which was another of the options the prime minister floated this week.

The bulletin also highlights the possibility of protests within Australia, although it says domestic protests are unlikely to be violent. It says Asio is not aware of specific threats to Jewish interests in Australia, although it says Israeli and Jewish interests remain “an enduring target of extremists globally”.

“While a small number of Australian-based individuals maintain a violent Islamist extremist ideology that includes a strong anti-Semitic element, we are not aware of any specific or credible terrorist threat to Israel or Jewish interests in Australia.”

Morrison on Tuesday flagged that Australia might follow Donald Trump’s controversial policy moving Australia’s embassy to Jerusalem – an announcement senior figures concede is timed to coincide with the Wentworth byelection this Saturday, which the Liberals are at risk of losing. If the Liberals lose the byelection the government will lose its one-seat majority in the lower house.

The electorate, held previously by the former prime minister Malcolm Turnbull, is home to a significant Jewish population. The reaction in Wentworth to the kite-flying has been mixed.

The Coalition considered the implications of Trump’s hawkish position on Jerusalem when Turnbull was prime minister, and dismissed the idea of Australia following suit because of a judgment that it would harm the bilateral relationship with Indonesia, Australia’s close neighbour.

Indonesia has reacted cooly to the potential shift, and representatives from 13 Middle Eastern and north African embassies in Australia have condemned the proposal, declaring it a “fatal mistake” that could lead to a breakdown in economic relations with Arab and Muslim nations.

The former Nationals leader Barnaby Joyce – who has once again put himself in contention for the leadership of his party – has warned the government “to be careful” not to imperil trade relationships as a consequence of any shift.

He noted Indonesia was the biggest buyer of Australian wheat and cattle, while the biggest buyer of live sheep was in the Middle East.

Joyce said he wasn’t proposing that the move would necessarily hurt trade relationships, arguing that countries were unlikely to stop trade with the US despite the Trump administration’s decision to move its embassy.

But Joyce said the Australian government has to “make sure we take them with us” and exercise “absolute care in this one”.

The Seven Network reported that the Indonesian foreign minister, Retno Marsudi, had sent Whatsapp messages to Australia’s foreign minister, Marise Payne, on Monday – shared with senior government members – in which Marsudi vented anger about the substance and timing of the announcement, which coincided with a visit by the Palestinian foreign minister, Riyad al-Maliki.

“Is this really necessary to do this on Tuesday? It will be a really big blow … It will slap Indonesia’s face on the Palestine issue,” the message reportedly said. “This will affect bilateral relations.”

Labor has blasted the move. The shadow foreign minister, Penny Wong, said: “Foreign policy, and Australia’s national interest are far too important to be played with in this fashion.

“The people of Wentworth, and all Australians, deserve a leader who puts the national interest ahead of his self-interest, and governs in the best long-term interest of the nation, not one prepared to play games with longstanding foreign policy positions five days out from a byelection.”

So far only the US and its ally Guatemala have moved their embassies to Jerusalem.