The government has defended a backlog of visa appeals saying increased scrutiny and subsequent refusals were behind the high numbers of challenges.

The number of visa appeals before the government tribunal that reviews cases has blown out to more than 60,000.

New analysis revealed by The Australian shows there was a 257 per cent increase in migration and refugee cases being reviewed by the Administrative Appeals Tribunal between July 2016 and August this year.

The data shows a surge in active appeal cases to 62,476 from 17,480 over this period.

The Morrison government said the backlog showed enhanced scrutiny and integrity within the system was working, with more permanent and temporary visa refusals.

But a migration law analyst from Macquarie University Dr Daniel Ghezelbash is concerned the blowout could mean the opposite.

"When you don't have a properly functioning review process then it really strikes at the heart of the integrity of the visa processing system," he told SBS News.

"I think a lot of this is spin and the government trying to put gloss on what is going on."

AAP

The Morrison government has progressively taken steps to strengthen the vetting processes of migrant and refugee visas, including greater use of biometrics and intelligence.

There was a 46 per cent increase in visa refusals for the permanent migration program in 2017-18 compared with the previous year. This figure has remained stable in 2018-19.

Immigration Minister David Coleman said increased scrutiny in the vetting process had resulted in a rise in the number of visa refusals.

"Our vetting processes are much stronger than those in place under Labor and have seen an increase in the number of visas being refused. We make no apologies for this," he said.

"The Coalition will always run an immigration program that is focused on integrity and quality."

This increased scrutiny has seen the average refusal rate rise slightly across the temporary and permanent visa programs.

The figure has risen to 3.3 per cent of applicants being refused a visa in 2017-18, up from 2.5 per cent in 2015-16 and equates to 96,724 more applicants.

Macquarie University

The average refusal rate was tracking at 3.8 per cent, between July 2018 and February 2019.

Meanwhile, more than 90 per cent of onshore protection visa cases are refused.

Dr Ghezelbash said the backlog in visa appeals linked to these refusals was a worrying trend for the visa management process.

"It is concerning on a lot of levels," he said.

"First you have got the uncertainty for the people that are waiting for this entire time, sometimes many years, with a very uncertain future.

"The precarious nature of their existence means they can't lay down roots or integrate into Australian society or contribute in a way they may otherwise be able too."

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In a statement, a spokesperson for the AAT said the backlog of lodgements was the result of "increased demand" for reviews of government decisions.

"In recent years, the AAT has received increasing numbers of applications for review of migration and refugee decisions," the statement reads.

"The number of applications lodged has quadrupled in the past decade and the trend is expected to continue."

The statement said the AAT's migration and refugee division received twice as many applications in 2018-19 compared with 2015-16.

"The division has implemented a range of efficiency measures and there have been some recent increases in the number of members available but we remain unable to keep pace with the growth in demand for these types of reviews."

About 75 per cent of government case decisions were upheld by the AAT among applicants between July 2018 and February 2019.

While the most recent AAT caseload report found 27 per cent of migrant and refugee applicants had their cases reviewed within 12 months of being lodged.

The backlog figure of more than 60,000 visa applicants was on par with cases the Administrative Appeals Tribunal had on hand at the end of last year.

However, data does show the number of new applications lodged with the Administrative Appeals Tribunal continues to rise.

Visa appeals rose 76 per cent up to 3,286 last month from 1,867 in July 2016.

While the number of decisions made by the AAT almost doubled from 1,153 to 2021.

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Dr Ghezelbash called for the visa processing system to be better resourced, to more efficiently deal with the number of applicants.

"The most important thing in that regard is having a decision making and a review process, that's fair and efficient."

"Obviously that's not happening right now with blowouts like this."

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This comes as the Coalition government attempts to push forward more legislation making it easier to deport foreign criminals currently before the senate.

The Morrison government’s crackdown on migrants with a criminal history on character grounds has seen 4,700 foreign criminals deported since 2014 after having visas cancelled.

But Dr Ghezlebash said only a "lucky few" of these decisions made on character grounds, have access to getting their decisions reviewed.

He agreed scrutiny is needed to ensure visa applicants were not taking advantage of the system.

"There are concerns about the integrity of the system and people putting in appeals to delay their removal," he said.

"But if we are concerned about the possibility of that happening... it is essential we have a well resourced AAT."