The hands of a New Zealand man detained on Christmas Island have been badly bruised after he was bound for more than 18 hours, his mother says.

RNZ News has been told that at least four New Zealanders were among a group from the Villawood centre in western Sydney who were flown to the island.

Ana Head's son Pita Mclachlan was one of them.

Originally from Hamilton, she moved to Sydney with her son in 2006.

Photo: SUPPLIED

Mr Mclachlan spent eight months in jail on a breaking and entering charge and three months at Villawood, before unexpectedly being moved to Christmas Island.

Ms Head was looking forward to her weekly visit to Villawood to see her son, but he sent her a message on social media on Thursday saying he had been sent away.

He told her his wrists were bound with cable ties for an hour and half while he waited to be transferred to the airport and then to the island, she said.

"From there the cable ties were taken off by scissors and he was put into handcuffs and they were left on all the way through to Christmas Island.

"He was then put into cable ties again and by the time he got [to the detention centre] he's had no feeling in his hands or wrists and he's got bruises all over them."

Mr Mclachlan repeatedly asked to sign the paperwork to allow him back into New Zealand but was refused, she said.

"Three times while he was in Villawood, twice when he was at the airport here in Sydney and he's been asking every day he's been on Christmas Island, so roughly about 10 to 15 times."

The process has left her devastated.

"When Pita told me on Thursday night, I was at work. I broke down that bad that I had to leave...I haven't been able to keep it together. Villawood still hasn't told me he has been transported to Christmas Island," she said.

"Our boys and families that are detained are being mistreated and the families left in the dark."

A New Zealander who had been at Christmas island for about five months, who wanted to be known as Ariki, said his new room-mate told him the group was handcuffed with cable ties at 6am at the start of the transfer.

"They were cuffed for 20 hours or so, maybe longer, from the centre to the plane to here - right up until they were inside the detention centre."

They were then put into a segregation cell for the night, he said.

Photo: Wikicommons

Australia's Department of Immigration and Border Protection would not comment, saying such matters were operational.

Christmas Island achieved notoriety last year when riots broke out after an escaped inmate was found dead.

Conditions in the island's detention centre have been widely criticised and one former Australian insider said the way the prisoners were being kept made riots inevitable.