The US is set to tell dozens of refugees held on the Papua New Guinea centre whether they will be offered resettlement in America within six weeks, according to a report by Reuters.
But Refugee Action Coalition spokesman Ian Rintoul has told SBS World News the development will only help a small group.
"There's only probably a third of the people on Manus Island have even had interviews and there's only about 70 people who've had medicals," he said.
"So there's no way they are going to go from 300 initial interviews to over 900 interviews in the next six weeks.
"I think we get some idea of the scale of the rejection when we understand only a small minority of refugees on Manus Island have even been interviewed."
Officials representing US Homeland Security returned to Manus Island this week to conduct medical examinations on 70 men.
Last month the men completed "extreme vetting" interviews with in-depth questions on associates, family, friends and any interactions with IS militants.
The deadline marks the first concrete timetable for the US-Australia refugee swap arrangement that sparked tensions between the allies after President Donald Trump described it as "a dumb deal" for America.
