Four out of every 10 appeals against Immigration New Zealand decisions have been upheld - leading immigration advisers to wonder if even more people may be missing out on residence because of flawed assessments.

An immigration lawyer said staff turnover, delays in processing and heavy workloads had led to inconsistencies and mistakes in visa processing.

One immigrant, who asked not to be named, said he knew people who had to leave the country as a result of bad decisions.

He was one of about 50 people to gain residence after a joint appeal to the Immigration and Protection Tribunal (IPT).

But he said he knew people who had given up and gone home.

"My perspective would be it was election time and during that time there was in the news that migrant numbers had to be cut down.

"They were not able to cut down student numbers or visitor visas, so they started pinpointing specific fields on the resident applications like chefs, IT support and retail store managers."

There was a 62 per cent increase in Immigration New Zealand appeals in the 2017-18 year - the highest in its history at 1927.

Most were for rejected residence visa applications and smaller numbers were appeals against deportations and failed asylum bids.

In the same period INZ refused 6000 residence visas out of 43,000 applications.

Successful appeals jumped from 29 to 41 per cent, with higher proportions for residence visas.

Immigration lawyer Simon Laurent said those numbers suggested more immigrants should be considering appeals.

It raised serious questions about INZ decision making, especially in residence visas, he said.

"There's a high level of churn in the staffing of Immigration New Zealand's visa services and the training may not be keeping up.

"So the standards applied are not being applied effectively because of the lack of experience of the people making them."

In about 80 per cent of the rejected cases, residence decisions were sent back to INZ for reconsideration because it had made an incorrect assessment.

Wrongly-declined visas could have life-changing ramifications, Mr Laurent said.

"They've either simply had to settle for staying on a work visa or realised they've come to a dead end."

Immigration adviser Arunima Dhingra said rejected partnership applications were also being pulled up by the tribunal, including a case where one of the grounds of refusal had been the wife not knowing which medicines her husband took.

"The yardstick that Immigration New Zealand has been using is, I believe, very shallow."

INZ officers were not looking enough into the complexities, cultures and contexts of applications, she said.

Appeals at time of policy change and more applications - INZ

INZ said the number of appeals to the IPT had fallen sharply since the start of 2018.

Assistant general manager Peter Elms denied the problem was down to staff turnover or how policy was being applied.

He said the incorrect assessments came at the time of a change in immigration policy and during a surge in applications from skilled immigrants.

"There were a large number of residence applications being submitted around that time in 2017. The greatest proportion of those residence applications were for the lower skilled end of the market.

"The quality assurance processes we have in the residence space are pretty good."

Residence decisions were also more consistent since being brought onshore rather than being processed overseas, he added.

The appeals tribunal, in its annual report, attributed the increase in appeals to changes in the application of immigration policies, and INZ efforts to clear backlogs.

(Source: 1NEWS NOW)