A New Zealand woman and her six-year-old son who live in Washington state have been detained by US immigration, according to American media reports.
Newsweek has reported Sarah Shaw and her son, Isaac were detained on the Canadian border three weeks ago after dropping her other children off in Vancouver.
It said she was waiting for a green card and was arrested despite having some immigration documents.
The Washington Federation of State Employees (WFSE) said Shaw and her son were being held at the Dilley Immigration Processing Centre in Dilley, Texas.
WFSE said Shaw worked as a juvenile rehabilitation employee at the Echo Glen Children's Centre in Snoqualmie - run by the Washington State Department of Children, Youth and Families.
The union was calling for their immediate release.
"The trauma this has already caused for her and her son may never be healed," WFSE president Mike Yestramski, a psychiatric social worker at Western State Hospital, said.
"But our union stands ready to help and support them in any way possible. An injury to one is an injury to all."
A fundraising webpage was set up by Shaw's friend, Victoria Besancon to get Shaw and her son back to Washington.
Besancon said Shaw had a "limited ability to communicate".
"She is relying on us to get her story out."
The Ministry of Foreign Affairs and Trade said it was aware of the reports of Shaw and her son's detention, and was seeking further information.
Foreign Minister Winston Peters said there were "scant details".
"Foreign Affairs and Consular Affairs are on to it now... I can't tell you any more than that," he said.
"We're trying to find out what the details are, we haven't got those details yet."
