Asylum seekers being held at one of Darwin's four immigration detention centres are now wary of talking to the media after two people who spoke to the ABC last week were sent to offshore detention.

More than 10 asylum seekers spoke on camera through the fence at the Darwin Airport Lodge last week, with some complaining of poor conditions and others saying they would prefer to stay in detention rather than face persecution or death in their country of origin.

They also complained that only two toilets were available for 500 people in one section of the Christmas Island detention facility.

Immigration Minister Scott Morrison last week said those complaints were "unsubstantiated".

Messages sent by asylum seekers from inside the Darwin Airport Lodge to Darwin Asylum Seeker Support and Advocacy Network (DASSAN) members this week reveal that two women, who spoke to the ABC on October 24, have been sent to Christmas Island.

"A guy from Immigration started talking about media. He said if you tell your story to the media, like why you came to Australia, it may affect your [application] process," one asylum seeker said.

Another said: "The people who were transferred to [Christmas Island] are those who spoke to the media last week."

Mr Morrison said claims that detainees were transferred offshore for speaking to the media are "completely false, and add to the growing list of unsubstantiated claims being promoted by advocacy groups through the media".

Mr Morrison would not say whether asylum seekers had been warned against talking to the media.

But he said "it has been long-standing policy of both Coalition and Labor governments that media are not given access to detainees".

Iranian couple arrived hours after asylum seeker law change

Fernanda Dahlstrom from DASSAN said last night's vigil was very different to the previous visits.

"We've been holding these vigils for over a year and every single week there's been a crowd of people on the other side of the fence," she said.

"This is the first week that we've seen virtually no-one come out to the fence to engage with the community. And we believe that's because they have been intimidated out of doing so by SERCO and immigration."

Last week, more than 20 asylum seekers came up to the detention centre fence to talk to the advocates. The ABC recorded interviews with more than eight of them.

At last night's vigil, only four asylum seekers came up to the fence, three adults and a small boy. An Iranian couple wanted to tell their story but not on camera, out of fear of retribution against their families in Iran.

The woman said she had already been recognised in Iran from a photograph of her with her head in her hands after the Australian Navy picked up her and her husband on July 19.

She said it "put our family into trouble and they're bothering and teasing our family and I think it's not good that our picture will be shown in our media".

Her husband said they had arrived in Australia just hours after the new laws came into effect under the previous Labor government, ruling out the possibility that people arriving by boat would be considered for permanent residency in Australia.

He said they did not know the law had changed.

"It's really not fair because we were on a boat [for three days]. We both are educated and we are just escaping from our country to make a better life," he said.

The couple said they cannot go back to Iran and they do not know what they will do when they are sent to Nauru or Manus Island.

The man said he suffers from epilepsy exacerbated by stress in detention.

"It started again on Christmas Island because of stress and those things. I can't walk correctly," he said.

The Iranian woman said Immigration officials did not tell detainees directly about the rules regarding talking to the media.

"I think it's obvious that last week everyone just rush here and talk with the media but today no-one came," she said.

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