Detainees who had nothing to do with the riot on Christmas Island were kept in cages, denied food and water and forced to urinate on the ground for more than 24 hours after police regained control of the facility, according to migration agent Marion Le.

Ms Le has written to Prime Minister Malcolm Turnbull seeking an inquiry into the response to the riot that caused around $10 million damage to the facility after the death of a refugee who had escaped. "Send fresh people to Christmas Island who are able to oversee what is going on there at this moment," she writes. "Believe me, it is not acceptable."

She kept in regular contact with a client who is challenging the cancellation of his visa and asserts he and others suffered "unconscionable abuse" after a terrifying ordeal.

"Those who were not involved in the riots and indeed were cowering unprotected in fear are being punished for simply being there," Ms Le wrote in a separate email to Immigration and Border Protection Department head Michael Pezzullo.

Her account is at odds with the department's official version, which asserts: "All detainees have been provided with food, water and shelter throughout the unrest at the centre."

Ms Le says her client was permitted to leave the "cage" he shared with some 40 others only after he agreed to be strip-searched, the day after order was restored to the centre.

"There has not been enough food and water, for some time some of them were in cages and with nowhere to pass urine or defecate except on the ground within the cages shared by up to 40 people," she writes in the email.

"The health issues are obvious. People who have loved ones on Christmas Island are unable to receive anything except very minor information such as 'All the detainees have been accounted for'."

Ms Le said she hoped "that out of this will come a willingness to accept that this abhorrent treatment of refugees, asylum seekers and long-term residents of Australia cannot continue and that there are other ways to deal with the issues and implement government policy".

The family of Fazel Chegeni, the refugee who died, has asked that his body be repatriated to Iran.

Meanwhile, a New Zealand MP has said ordinary New Zealanders could decide to boycott Australia in protest against the treatment of detainees.

"I think there will be a lot of people who will make that sort of call and who will decide one way of venting their protest is not to go to Australia," Peter Dunne said on Radio New Zealand on Friday.

"Or they could make their concerns known to Australians they know, relatives or friends – this is something that needs to be taken up people-to-people.

"The Australians keep telling us we're family, and families are frank with each other."

Mr Dunne said in a newsletter published on Thursday that Australia's actions amounted to using "a modern concentration camp approach" to detain New Zealanders with criminal records.

He said Australian authorities were pushing the boundaries of human right.

"We can, and should be, speaking out as loudly and frequently as we can against abhorrent practices.

"The government and the opposition need to be turning on the real villains of the piece – ministers like Peter Dutton and others in the Australian government who continue to promote and support such savage and inhumane policies."

With AAP

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