Penny Wong has told her Israeli counterpart that Australia supports Lebanon’s sovereignty and does not want to see the southern part of the country occupied by Israel, after the Netanyahu government revealed plans to pursue a “defensive buffer” against Iran-backed armed group Hezbollah.

It comes as Israel vowed to continue striking Iran, dimming hopes of de-escalation even as the US president, Donald Trump, talked up the prospects of a deal to end the conflict.

The Guardian reported Israel’s defence minister, Israel Katz, said Israeli forces would “control the remaining bridges and the security zone up to the Litani” – a river that meets the Mediterranean about 30km north of Israel’s border.

Wong said she spoke to Israel’s foreign affairs minister, Gideon Sa’ar, on Tuesday night to reiterate Australia’s condemnation of Iran and concern over the ongoing conflict at the strait of Hormuz.

But Wong, who has previously clashed with Sa’ar, was firm on Australia’s opposition to any Israeli seizure of Lebanese land.

“Australia is gravely concerned at the expansion of the conflict in Lebanon, the loss of life and displacement of more than one million civilians,” she said on Wednesday.

“We discussed Hezbollah’s continued strikes on Israel and agreed they must disarm in line with previous agreements.

“Australia supports Lebanon’s sovereignty – so we do not want to see occupation of southern Lebanon by Israel.”

Wong also advised “Australians in Lebanon to leave now, if safe to do so – please do not wait until it’s too late”.

The Department of Foreign Affairs and Trade estimates about 15,000 Australians reside in Lebanon. Since the outbreak of the war, more than 8,000 Australians and permanent residents have returned from the Middle East from across the region.

In a post to social media, Sa’ar said he had emphasised to Wong “the massive scale of missile, rocket, and drone attacks against Israel from Lebanon”.

“Israel is acting to defend its communities and citizens,” Sa’ar said.

“I described the reality of life these days in our northern [Israeli] communities, to which residents returned after over a year in which they didn’t live in their homes.

“Unfortunately, the Lebanese government is not taking practical steps against Hezbollah, neither to stop the attacks on Israeli civilians, nor in other contexts.”

Over the weekend, Australia announced an extra $5m in aid to support civilians in Lebanon, particularly women and children, impacted by the conflict.

It is understood Wong and Sa’ar also discussed a number of other issues likely to fan lingering tensions between Australia and Israel.

Among them were comments made by the Israeli finance minister, Bezalel Smotrich, who was sanctioned by Australia last June and has backed moves for a “new border” with Lebanon from the Litani river.

Australia’s mission to the Palestinian Authority in Ramallah remains closed more than seven months after Israel revoked Australian diplomats’ visas in retaliation.

Guardian Australia understands the Albanese government is continuing to press Israel for their return.

Escalating settler violence in the West Bank was also discussed, as Israel tightened its control over the occupied territory.

In February, Israel amended laws, overturning a ban on the sale of land in the West Bank to non-Arabs and transferring authority over building licences from the Palestinian-run municipality to the Israeli civil administration.

Katz and Smotrich issued a joint statement after the measures were passed: “We will continue to kill the idea of a Palestinian state.”