The family of a New Zealand woman detained by US Immigration and Customs Enforcement (ICE) is pleading with the New Zealand government to help secure her release, claiming she is confined to a room with 46 people for 22 hours a day.

Everlee Wihongi, 37, moved to the US with her family aged six, and holds a green card, her mother, Betty Wihongi, told local broadcaster RNZ.

The family visited New Zealand in March for an uncle’s 80th birthday, but when they flew back to Los Angeles on 10 April, Wihongi was detained.

After a seven hour wait, the family received a phone call from Wihongi saying there had been an issue with a historic conviction and she had been sent to an ICE processing facility.

The family told RNZ Wihongi had a conviction for possession of marijuana dating back more than a decade and she had travelled in and out of the country several times without issue.

Wihongi faces another six weeks in detention after a judge set her recall date for 10 June.

Wihongi was feeling “very anxious” over what the outcome would be, Betty said, while the experience had damaged the family’s view of the US.

“This place no longer feels like home to us, especially after seeing how my daughter’s been treated,” she said.

The family has called on New Zealand’s ministry for foreign affairs, and its minister, Winston Peters, to intervene.

“Step up and do more,” Betty said. “One, do something about Everlee, there has to be something the New Zealand government can do; and two, train your people … because the help we are getting is not the best”.

In a statement to the Guardian, the ministry said it could not comment on the specifics of the case due to privacy reasons but said it was providing assistance to the family of a New Zealander detained in Los Angeles.

It said it could not influence the immigration decisions of other governments.

The Guardian has also contacted Peters’ office. Speaking to reporters on Wednesday, Peters said Wihongi had not declared a prior conviction on her immigration paperwork.

“When the form asks you to do things, complete the form accurately,” he said, adding staff had been working on the case “from day one”.

“This is going through a process internationally. The process has got to be followed. We cannot intervene. We can do our best to help, but that’s all we can do.”

The Guardian has contacted the Wihongi family and ICE for comment.

Wihongi’s case is the latest in a growing list of foreigners facing interrogation, detention and deportations at the US border, including New Zealander Sarah Shaw and her six-year-old son, and more recently an Egyptian family of six, and an 86-year-old French widow.

According to Guardian analysis, 60,310 people were in detention as of 4 April, and 468,450 people had been deported since Trump’s inauguration.