A US federal public defender in Hawaii, Alexander Silvert, says a court will have to decide who has the jurisdiction to enforce the law in American Samoa.
A resolution made by the territory's senate recommends that US federal officials should take over responsibility for immigration and customs.
This follows a recent crackdown on overstayers by American Samoa's Attorney General.
Mr Silvert had represented the owner of the now closed Daewoosa Factory, Kil Soo Lee, in a human trafficking case involving the hiring of 250 Vietnamese and Chinese nationals for jobs in American Samoa.
He says during that case he discovered that more clarity was needed in the enforcement of law.
"American Samoa would contend that this is American Samoan law, governed by territorial law, and any issue of enforcement would be strictly a matter for American Samoa courts. The FBI I believe is taking a different approach and believe it has authority under United States law to interpret and to investigate violations of territorial immigration law. I know this is a struggle and an ongoing debate"
Alexander Silvert, a Hawaii based federal public defender