The men from Sri Lanka, Afghanistan, Iraq and Iran had been held on the Indian Ocean outpost of Christmas Island but were brought to Sydney on Saturday after their applications were rejected, Immigration Minister Chris Evans said.
"As you could understand they, many of them, are not happy with that result and so for management purposes we thought they were better dealt with in a high security detention centre on the mainland," Evans told reporters.
Evans said he was concerned the men could hurt themselves or others if left on Christmas Island, which has been filled to near capacity in recent months by the arrivals of boatloads of asylum seekers.
"In the past we have had history of people self harming and taking other action to try and prevent their removal from Australia," Evans said.
"That requires us to be very sensible and careful about our management of that group."
Boatpeople arriving in Australia are automatically transferred to the purpose-built facility on Christm