Australian consular officials are on their way to a notorious Israeli prison, where activists, including five Australians, are thought to be detained.

They were part of the international flotilla intercepted by the Israeli navy while trying to deliver aid to Gaza, with anxious families back home still waiting for contact.

“He said ‘I’ll get back to you, I’m just steering the boat’,” Hudayfa Rafiq, the brother of Sydney content creator Abubakir Rafiq, told 9News.

”We have not been able to speak to my brother directly since 3am yesterday.”

Abubakir, who was aboard Spectre, is one of five Australian citizens who were part of the Gaza Sumud Flotilla believed to now be detained in Ketziot, a notorious Israeli prison.

“This is a peaceful civilian mission and it is legal under international human rights law,” Talitha Mitchell from Gaza Sumud Flotilla said.

The Israeli Foreign Ministry says it plans to deport the hundreds of activists involved but Australia has so far struggled for information on the ground.

“We had made a formal request to the Israeli authorities for an update on any Australians who are being held in detention,” Health Minister Mark Butler said.

Opposition Leader Sussan Ley said the Liberal party “expect everyone who is Australian and is detained to get the appropriate consular help”.

The Department of Foreign Affairs and Trade said in a statement it had warned Australians repeatedly not to breach Israel’s naval blockade because of risks to their safety but it’s also calling on Israel to allow humanitarian aid into Gaza.

“Australian officials in Tel Aviv are liaising with Israeli authorities and have formally requested confirmation of the detention of any Australians and early consular access,” a DFAT spokesperson said.

“Australia calls on all parties to respect international law, to ensure the safety and humane treatment of those involved.

“We understand that people want to help deliver aid to those suffering in Gaza – we also want to see critical aid delivered.”

Deputy Greens leader Mehreen Faruqi slammed the government’s response.

“All they can do is issue warnings to them rather than ensuring their protection and their safety,” Faruqi said.

Abubakir Rafiq’s sister Hajar Rafiq added that it won’t deter her brother or people like him.

“I can tell you 100 per cent if he had the chance again he would go again because people want to see change,” Hajar said.

The Global Sumud Flotilla (GSF) consisted of about 50 boats and 500 activists from 44 nations, including Swedish climate change campaigner Greta Thunberg.

They set sail from Barcelona a month ago with the goal of delivering food, water and medicine to the people of Gaza.

Israel has made it clear that it does not want this to happen.

Independent Senator Fatima Payman today named six Australians who she said have been arrested by Israeli authorities.

“I am deeply concerned by reports that Australian citizens – Surya McEwen, Abubakir Rafiq, Hamish Paterson, Juliet Lamont, Bianca Webb-Pullman and Dan Coward – have been arrested by Israeli authorities after attempting to deliver aid to Gaza as part of the Sumud Flotilla,” she said in a statement.

Payman urged the Australian government to ensure they were treated humanely by Israel.

“Australia must not remain silent when its citizens are detained for acting on conscience and compassion,” she said.

The Maritime Union of Australia said today Hamish Paterson was a member of the trade union.

National secretary Paddy Crumlin urged the federal government to ensure immediate consular assistance for him and other detained Australians.

“The Sumud Peace Flotilla is a peaceful mission of trade unionists, humanitarians and aid workers delivering vital assistance to Gaza,” he said.

“Their ‘crime’ is non-violence, solidarity, compassion. Their detention is a violation of fundamental human rights and international law.”