Greens Senator Nick McKim says he is being threatened with deportation from Papua New Guinea after trying to visit the asylum seeker facilities on Manus Island.
Senator McKim told SBS News he went to East Lorengau camp on Thursday but was denied entry and had his passport taken.
He said his passport was returned but shortly after "one immigration official and four heavily-armed police officers" stopped him nearby and told him an "official deportation notice" would be issued within hours.
The senator is visiting Manus Island this week to mark .
He said his visit was "polite and respectful" but most importantly legal, having been granted a 12-month multiple entry visa.
"I'm very disappointed that they are threatening to deport me because I am here to expose the truth about the treatment of refugees, to lift the veil of secrecy that's been draped over Australia's offshore detention regime," he told SBS News.
"It's part of my job as a senator to do this, to hold the government to account."
The senator said he was yet to be given an official reason as to why he was being deported.
"I'm not going to wait in my hotel for these guys ... I'm going to continue what I've got planned here today," he said.
"Whatever happens to me, I'm going to be back in Australia in 24, 48, 72 hours, but many hundreds of people are still going to be here in Papua New Guinea, without hope for the future."
Earlier on Thursday, he told SBS News the situation on the island was "worse than it's ever been" as a "great depression" has taken over the refugee population since the May election.
"Many refugees ... were expecting a different outcome in the election. They thought if the Labor government came to power they would activate the New Zealand arrangement and there would be opportunities for people to go to New Zealand," he said.
Labor had indicated if they won the election they would accept an offer to resettle refugees from Australia's offshore detention centres, which the Morrison government has opposed.
"That removal of hope has been the final blow in terms of the mental health of so many refugees ... It's led to a great depression among the refugee community here and led to a significant spike in self-harm."
"I was here two years ago ... It's hard to believe but I genuinely feel that the situation for the population here that remains is worse than it's ever been."
Senator McKim said he met several refugees on Wednesday who had been on the island for the full six years, including one man who arrived as an 18-year-old.
He said the other "very clear message" he was getting was "that many simply do not want to come to Australia".
"They no longer want to come to here. They just want to be set free in a place where they can have freedom and safety that they deserve."
He also met a number of refugees in Port Moresby, who were there for medical reasons or waiting to be transferred to the US, under a refugee swap deal negotiated by the Coalition in 2016.
"In Port Moresby, their movements are significantly curtailed, they are only allowed out of their hotels for a few hours per day and are then required to come back to their hotels," he said.
"So there is effective ongoing detention of people both on both Manus Island and in Port Moresby where movements are restricted to various degrees."
He said the six year anniversary should act as a wake-up call for Australia.
"[The men on Manus Island] are like the corpses that were impaled on the walls of medieval cities thousands of years ago to try and dissuade other desperate people from trying to enter," he said.
"It is a dark chapter in our country's story and it is time we drew it to a close."
SBS News has contacted the Department of Home Affairs about Senator McKim's observations and claims.
In an email earlier this week, the department confirmed 457 asylum seekers remain in Papua New Guinea.
"No one subject to regional processing arrangements will be resettled in Australia," the spokesperson said.
The spokesperson defended the care offered to these individuals.
"Transferees continue to be provided with a range of health, welfare and support services, including extensive physical and mental healthcare provisions, free accommodation and utilities, allowances and employment services."
After a major spike in boat arrivals, then-prime minister Kevin Rudd announced on 19 July 2013 that all asylum seekers who came to Australia by boat would be sent to Manus Island.
Weeks later, the Labor government announced a similar arrangement with Nauru.
The hard-line stance was continued by the Abbott, Turnbull and Morrison governments.
