The Federation for American Immigration Reform has expressed surprise at a deal allowing Australia to settle some of its refugees in the United States.
The group said Americans should have been told before last week's presidential election about the Australian-US negotiations for refugees kept on Papua New Guinea's Manus Island and Nauru.
A spokesman for the group Ira Mehlman said it was basically a slap in the face to the voters who made their position clear last week.
He said he believes any transfer would have to be completed before Donald Trump is sworn in as president on January 20.
However, Mr Mehlman said it was hard to imagine they could resettle everybody within that timespan.
There has been no word from the incoming US administration about the transfer programme.