The Cook Islands Immigration Department is giving one month's grace to those without entry residence and work permits to ensure they have the necessary documentation.
The Principal Immigration Officer, Tutai Toru, says those continuing to flout the rules after the grace period run the risk of deportation.
Mr Toru says the problem has developed rapidly because of employers, particularly companies running fishing boats, who employ people but never get them registered properly.
"We have about thirty-six fishing boats licensed to fish in Cook Islands waters and each boat carries a crew of about five. The bigger boats go to about 20 but we only cleared about six of those boats. There are 30 others that never cleared with immigration so we are telling everybody to tidy it up get everything up to date and they have about one month to sort it out."
The Cook Islands Principal Immigration Officer Tutai Toru