By Kat Wong in Sydney

Israeli naval officers have begun boarding vessels in international waters, with concerns for five Australians involved in an aid flotilla bound for Gaza.

Bianca Webb-Pullman was aboard Florida, one of the boats intercepted by Israeli forces about 2pm on Thursday (AEST).

Video from the Florida shows naval officers boarding with weapons raised as life-jacket-clad passengers raise their hands.

The vessel is among more than 30 comprising the Global Sumud Flotilla attempting to reach the Palestinian territory.

Sydney man Abubakir Rafiq is believed to have been on another boat named Spectre that was intercepted earlier in the day.

Juliet Lamont and Hamish Paterson were on the Wahoo, believed to still be sailing along with MiaMia, which is carrying Surya McEwen.

Dr Webb-Pullman sent one last message to her mother before throwing her phone overboard before the Israeli interception.

“Even if I die, don’t worry, it was still 100 per cent worth it,” she wrote.

Her mother, Julie Webb-Pullman, has received updates from the flotilla’s family liaison but said the Australian government’s response had been “reprehensible”.

“If she has to die because this government is not doing what it should be doing, then that’s an indictment of the government and I will not forgive them,” she told AAP.

Australians have been warned not to travel to Palestine since the October 7, 2023, attack by Hamas on Israel, which sparked the conflict engulfing Gaza.

The Department of Foreign Affairs and Trade has added specific advice on accessing the besieged strip by sea.

“Israel has a naval blockade in place along the coast of Gaza. Don’t join others seeking to break the blockade,” DFAT’s Smart Traveller website says.

“Previous attempts to break the blockade have resulted in death, injury, arrest or deportation of foreigners.”

To those in the flotilla, the desperate humanitarian landscape in Gaza makes the aid mission worthwhile.

Ms Lamont said about 30 Israeli boats had surrounded the flotilla and was pounding boats with water cannons, before attempting to board.

“It does seem at this stage they are unprepared to sink the vessels or to kill anyone,” she told ABC Radio.

“We’ve just got to keep steadfast, keep dodging them, keep moving forward.”

A Gold Coast man who awoke to a “ball of flames” when his flotilla boat was hit by a drone in early September also criticised Australia’s response.

“After the drone strike … I have heard nothing from the Australian government – no email, no phone call, no check-up,” Yusuf Omar said on Wednesday.

Before the interceptions, Assistant Foreign Affairs Minister Matt Thistlethwaite said he was concerned for the safety of Australians on the flotilla and called on Israel to refrain from “any unlawful or violent act”.

“We understand people are distressed and want to respond to the humanitarian catastrophe in Gaza – we also want to see critical aid being delivered,” he said in a statement.

Israel’s foreign ministry said several vessels had been “safely stopped” and its passengers, including Swedish activist Greta Thunberg, had been transferred to an Israeli port.

“They are not interested in aid, but in provocation,” the ministry said on social media.

Israel has been throttling aid into Gaza for months, leaving more than 641,000 people facing catastrophic levels of starvation, according to United Nations data.