A Department of Immigration spokesman told AAP some detainees had skipped meals but he was unable to confirm media reports of a large-scale hunger strike.
"There are people who have missed meals," the spokesman said on Saturday.
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He stressed any hunger strike action would not influence offshore processing plans.
"Anything these people can do will not change government policy," he said.
"We continue to work with them and advise them on the situation, but this (the plan for transfers) is happening."
Fairfax Media reports that 238 people from Afghanistan, Pakistan, Iran and Sri Lanka, including 40 women and children, had been informed on Friday that they would be sent to Nauru for processing and deported to their home countries if they did not cooperate.
One Afghan asylum seeker told Fairfax he had begun refusing food on August 16, after arriving by sea from Indonesia two days earlier.
Federal parliament recently passed legislation to allow offshore processing of asylum seekers who arrive by boat.
An independent panel recommended the government urgently restart offshore processing on Nauru and Papua New Guinea's Manus Island.
