"I will be unlawful in New Zealand in a few weeks and I'm feeling incredibly frustrated and stressed," Han said.
"Two years of waiting for a decision is really a nightmare for me and my family."
Han's husband holds a work to residence visa under the long-term skills shortage list and earns in excess of $100,000.
The couple have two children, aged 3 and 1.
Han claimed her employer had been asked up to eight times to submit additional documents to INZ, some of which were repeat requests.
"Each time the company's accountant and admin had to spend a massive amount of time to prepare the files," Han said.
"I know it's our obligation to do so, but after so many times and still without any result, it's been really frustrating and stressful."
Han said both she and her husband are graduates with masters degrees from "very top universities in China", and had found skilled jobs within three months after getting their work visas.
An INZ spokeswoman confirmed both of Han's applications were currently being processed.
She said the applications had taken longer because during the assessment process, the agency had required further information from her employer on a number of occasions.
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"All INZ offices were closed during alert level 4 and the processing of SMC residence applications was on hold during that time," the spokeswoman said.
"As these are paper-based applications, it was not possible for this work to be done from home during lockdown."
She said the processing of work visa applications were also on hold during lockdown level 4, except for jobs related to the Covid-19 response.
"This contributed to the time taken to progress the processing of both Ms Han's applications in recent months," the spokeswoman said.
When its offshore offices began opening under alert level 3 and 2, INZ was required to adhere to strict guidelines, she said, and had to limit the number of staff returning to offices.
This also impacted on the number of residence applications being worked on.
"INZ acknowledges the delay that has occurred in the processing of Ms Han's residence application in particular," the spokeswoman said.
"Residence applications take longer to process as there is more at stake and there is greater scrutiny of each application, which means there is a flow-on effect and the allocation of new applications to an immigration officer can take longer."
The spokeswoman said going forward, the agency had formalised the priority allocation of some applications for highly paid applicants and applicants with current occupational registration.
"This intended to allow INZ to start allocating older, non-priority applications on a more consistent basis," she said.
"INZ continues to process residence applications at the same volume and with the same level of resourcing while the Government works through the new New Zealand Residence Programme."
The spokeswoman said INZ would continue to process Han's applications and would be in touch with her on their progress.