There's no electricity, the rooms are cramped and there's no fresh water.

This is how a group of almost 600 male refugees are living on Manus Island – ill, fearful for their lives and right in the middle of a "humanitarian crisis', and now for the first time it’s been caught on camera.

Activist group GetUp has revealed the extent of the filthy conditions the men are in after being smuggled in to the former detention centre by locals.

But the footage has done little to amend the government’s message, with federal cabinet minister Christopher Pyne saying the men are “effectively squatting” during his regular appearance on TODAY.

“They are choosing to stay in those conditions. That is the fact of the matter,” he said.

“Many of them have been told by Australian activists to stay in Manus Island and they'll get them to Australia.”

The shocking footage shows up to 40 men sleeping in one room, where temperatures often exceed 40 degrees.

Up to 40 men are sleeping in one room, some on mattresses. (Supplied)

The men say they're too afraid to relocate to alternative accommodation. (Supplied)

The water has been switched off and dirt has piled up on every surface, including the toilets and showers.

"The conditions we witnessed on Manus are worse than anything we have ever seen. Death or serious illness is inevitable in coming days," GetUp’s human rights director Matthew Phillips told 9news.com.au.

Despite running out of food, medication and drinking water, they believe it's safer to remain in the compound than risk being attacked by locals at new facilities near the main township of Lorengau.

The footage shows the filthy conditions of the rooms in the detention centre. (Supplied)

There is no running water. (Supplied)

Federal Labor MP Anthony Albanese has hit out at the government and said it is no wonder these men “have this frustration after years of indefinite detention.”

"Manus was supposed to be a processing centre. Instead, it's become a place of indefinite detention,” he said.

“For many of these people, they don't see hope in terms of settlement in a third country. The government looks at these people and doesn't see human beings deserving of respect, they see a political opportunity.”

“The truth is, the government hasn't provided options of third country settlement for these people. New Zealand have made an offer and the government rejected it. They'd rather have this stand-off and it's time that the politics ended and that the government actually put in place a plan and took some responsibility.”

The toilets are dirty and the men claim they're getting ill because of it. (Supplied)

Further footage released by GetUp appears to contradict the government’s claims of resettlement for the men on Papua New Guinea.

Alex Rashid, 22, is a Rohingya who fears he will be killed if he is returned to Myanmar.

Mr Rashid fled his homeland more than four years ago by boat and ended up at Christmas Island before being transferred to Manus Island three days later.

He is now attempting to settle in Papua New Guinea, where he has two children and a wife.

But his travel permit and identity document have not been renewed since expiring in January, and he is unable to afford the PNG immigration processing fees.

“I just want Australia's help to stay here and start a life with my family. Nothing else. Please help me,” he said.

Meanwhile, activist groups are stepping up their efforts to raise awareness for the plight of the 600 men remaining in the squalid facilities at the Manus Island detention centre, who fear for their safety if resettled at other locations in Lorengau.

Five climbers illegally scaled the Sydney Opera House on Thursday attempting to unfurl a banner which said ‘Evacuate Manus #BringThemHere’.

However, the Whisteblower Activist and Citizens Alliance members were apprehended by police moments before unfurling the 60-metre banner.

A smaller sign, reading ‘Australia world leader in cruelty’ was displayed for a short time.

The protesters chanted “we had no choice” as they were led into a police van after being charged with trespass.

They were issued with place restrictions not to enter the Sydney CBD and will face the Downing Centre Local Court on December 20.

Two of the activists (inset) during their protest on Thursday (Image: Supplied)

Members of the same organisation unfurled a banner off a crane at Flemington on Tuesday ahead of the Melbourne Cup.

Another woman was arrested after driving her car on to train tracks near Flemington Racecourse.

The car’s tyres had been let down and ‘Evacuate Manus’ was spray painted in pink on its bonnet.

Police found the woman “bolted” to the steering wheel.

Actor Russell Crowe says Australia's treatment of refugees at the now-closed detention centre on Manus Island is "disgraceful" and has offered to find six of them jobs .

He took to Twitter last week to voice his opinions on the issue.

"Manus. A Nations (sic) shame. Lives held in limbo. Lives lived in fear & despair . It's f---ing disgraceful," he said.

Crowe has since reached out to Prime Minister Malcolm Turnbull to ask how he can “simplify the mess.”

But Mr Turnbull, like Mr Pyne, is standing firm on the government's position - also levelling blame at Australian activist organisations.