A New Zealand woman with a brain aneurysm may have her partner sent back to America.

But Elizabeth Bradley, 49, says she was led to believe by her immigration adviser that the Immigration New Zealand (INZ) decision to decline her American partner's work visa was "made in China".

Bradley, a librarian from Mt Albert, was so outraged she wrote to her MP, Prime Minister Jacinda Ardern, slamming the fact that a Chinese citizen was making a decision about who could live in NZ.

"It's hard to believe any Kiwi would accept any decision made on their behalf by a citizen of a foreign country," Bradley said in the letter.

"I was astounded to learn that the person making this decision that so greatly affects my life and future was not a New Zealander."

But Immigration New Zealand confirmed today that the visa officer was in fact based in Auckland, despite the fact that he has a Chinese-sounding name.

"It should be noted that the decision to decline the application was due to INZ not being satisfied that (Ken) Chertok and his partner were living together in a relationship that was genuine and stable," INZ manager Michael Carley said.

Bradley believed she had been misled by their adviser Tuariki Delamere about who made the decision.

"According to Tuariki, the visa was declined by a Chinese man based in Shanghai," she said.

"(We) naively believed our licensed immigration adviser was a professional with only our well-being at heart."

Bradley said this left her shocked that a person in another country could decide and make judgments on the life and future of a New Zealander.

Delamere did not return the Herald's call, text or WeChat messages.

"Mr Delamere was very much mistaken when he told us that the INZ staff member who rejected our application was in China," she said.

"He encouraged us to go to the media with this fact and at no time ... has he corrected his error."

Bradley claimed Delamere had known at some stage that the officer was not China-based.

Bradley, who has worked with Auckland libraries for 30 years, is diagnosed with an aneurysm and said Chertok, also 49, has been an "immense support".

"I have no family in this country and Ken has been absolutely wonderful, waiting with me in emergency all night, attending appointments and helping me understand the diagnosis and tests I went through," she said.

The couple met four years ago on Twitter and Bradley flew to visit him in Seattle in 2016.

Chertok, a former lawyer, came to New Zealand on a visitor's visa last year and has been living with Bradley.

But over the period, he did travel back to the United States to work on a potential business and visiting family.

They received a notice from INZ in May that Chertok's application for a partnership visa was likely to be declined due to a lack of continuity of living together.

The couple requested an interview, but their request was turned down by the case officer.

"Ken is my life partner, my love and my best friend," Bradley said.

"We have supported each other through the trials of life over the last four years and have come to depend upon and love each other deeply.

"We count ourselves as immensely lucky to have found each other, as being the other half of our heart."

Chertok said they were planning a future together, including buying a house, getting married and establishing a business in Auckland.

He is also helping to grow MyRivr Trust, which aims to make crisis and health services readily accessible to Maori and Pacific Islanders through an app.

"We are deeply in love and I truly cannot imagine life without Liz," he added.