Lawyers for Tongan overstayers conned by a residency visa scam want a written agreement from the government that protects victims who go to the police.
Up to 2-thousand Tongans are estimated be victims of the scam but lawyers say many are too scared to lay complaints.
The police in south Auckland say the fear of being deported is a barrier to their inquiry.
They joined Immigration officials at a public meeting over the weekend to reassure victims they wouldn't be deported during the inquiry and would have their cases reviewed afterwards.
But one of the lawyers who called the meeting, Amelia Schaaf, says a verbal assurance isn't enough.
She says the lawyers want a meeting with government representatives to set clear procedures for reporting immigration scams.