Lawyers acting for state abuse victims say some are signing away rights, and could be incriminating themselves as part of the Royal Commission of Inquiry.
The inquiry, which starts in Auckland on Tuesday, will look into instances of abuse between 1950 to the end of 1999.
State abuse lawyer Amanda Hill told The AM Show there was a lack of clarity about the rules of the inquiry.
Hill said some scenarios have dented the trust of survivors.
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"I think they are exposed," she told The AM Show on Tuesday. "They aren't clear about what is happening with the commission, and they aren't clear about the rules.
"So many of the people who went through the homes and foster care, later offended. It's an unfortunate reality that people who were children in state care have a higher chance of offending."
The inquiry isn't looking at individual compensation, but wants to hear from those who have been through the historical claims process.
"Part of the story the commission needs to hear is that impact," Hill said.
"If people are talking to the commission about that, then they need to be aware [of] what the potential implications are.
"Not all our clients read very well - there isn't a very good level of literacy amongst survivors of state care, and so if you don't understand what you're signing, then there are real problems with that."
The Royal Commission is expected to run for nearly three years, although this may be extended if more time is needed.