26/11/2017 10:15 PM AEDT | Updated 26/11/2017 10:20 PM AEDT

Medical Aid Denied To Manus Refugees As Thousands Protest

MSF (Doctors without Borders) are pleading with authorities to medically assess the Manus Island refugees.

Thousands have protested across Australia's major cities over the treatment of Manus Island refugees amid news that humanitarian organisation Médecins Sans Frontières (Doctors without Borders) were denied access by Papua New Guinea immigration.

Despite MSF receiving approval from authorities to enter the detention centre to assess the men on November 19, the organisation said it had been prevented from entering the transit centres since arriving on Manus Island on Wednesday.

MSF doctor and president of MSF Australia, Dr Stewart Condon, expressed concern for the refugees' physical and mental health and urged authorities to grant the group access.

"On Thursday 23 November, we met one man who was later taken by ambulance from the RPC to Lorengau General Hospital. He appeared to be dehydrated, malnourished and showing signs of severe depression, but we were not able to speak with him for any length of time," Condon said in a statement on Sunday.

"MSF remains concerned about whether the medical and psychological needs of the men are being met, and whether the local structures have the capacity to care for them. The situation here is volatile and the MSF team remains on standby to give any medical humanitarian support we can."

Following the refugees' forced removal from the decommissioned detention centre on Friday, snap rallies were organised around the country to protest the treatment of the men. Video footage taken that day appeared to show Papua New Guinea police hitting the unarmed men with steel rods, with asylum seekers using social media after the incident to show photos of injuries sustained from the "violence and aggressive behaviour".

World Vision Australia chief advocate Tim Costello had been on Manus Island when PNG police stormed the centre and described the "bruises and lumps on their [the refugees'] heads" in the aftermath.

"There were no broken bones. It wasn't over the top violence. More scrapes, bruises, their things were trashed first and much of it taken. And then those who resisted were dragged or forcibly put on buses," Costello told 'The Project' on Sunday night.

Costello, who had been visiting the Island on a fact-finding mission for the humanitarian body, the Australian Council for International Development, reiterated the claim of many refugee advocates and the asylum seekers themselves that the new camp they had been forcibly moved to wasn't finished and was too small to house all the men.

"We saw open drains.., concrete mixers, earth-moving equipment. We saw pictures from UNHCR who have been in there taking pictures of the one toilet block [which is] under water. It's all just a work construction site still," Costello said.

"But if Peter Dutton doesn't believe me or the United Nations, he shouldn't mislead the public. He should get on a plane, go up tomorrow, see what I saw and then level and tell the truth to the Australian public."

Manus Island detainee and journalist Behrouz Boochani thanked all those who had protested over the weekend on his and the other refugees' behalf.

"I really appreciate the people who stand up for humanity and have supported the people in Manus across Australia today," he wrote on Twitter on Sunday night.

"You are beautiful people. Much respect to you all. Thank you."