Australia’s vast visa backlog is trapping engineering graduates out of the country for up to four years, compounding the skills shortages and causing heartache, frustration and depression among applicants.

The engineering job vacancy rate has increased 97% in 12 months, something the main industry body, Engineers Australia, fears could have a “catastrophic” impact, including by delaying major infrastructure projects relied upon for the nation’s economic recovery.

The wait times for the 476 visa – designed for recent engineering graduates who want to live, work or study in Australia for up to 18 months – has blown out to a staggering 41 months since 2018.

That has left people like Gurpreet Kaur, an engineer based in India’s Punjab state, stuck waiting for almost four years, having to submit and resubmit paperwork and evidence, but unable to speak to anyone directly within the home affairs department about her application’s status.

“I personally applied for this visa back in September 2018 and am still waiting for my visa grant,” Kaur told the Guardian. “Despite meeting all the criteria, paying the application fee, medical assessment fees, there are still a lot of applicants like me from Sri Lanka, Pakistan and Bangladesh and many more countries … about 6,000 applicants are waiting for their grant.

“Waiting for three to four years, it’s a really frustrating situation and I think it’s a moral duty of any government, because this is unfair to us. We have planned all our career plans, we are suffering, not only professionally but it is a mental depression also.”

It’s a similar story for Muhammad Altaf, who lives not far from Islamabad in Pakistan.

Altaf applied for a 476 visa in 2019 and his career has been on hold since. He said he understood that Covid-19 had necessarily disrupted visa processing, but said, since the border reopened, the processing times had not improved in any way. Both Kaur and Altaf are in social media groups with a large number of other 476 visa applicants, who keep in constant contact about their progress.

“The last 10 days, they’ve only granted one visa,” he told the Guardian. “So if this process continues at this pace, then I think we will get our grants in three or four more years.”

A recent freedom of information request showed the department still had more than 6,000 applications for the 476 visa, which it was yet to process.

India’s high commissioner to Australia, Manpreet Vohra, said visa processing delays were a problem.

“I believe it’s a problem, but only because of staff shortages and backlog built up because of the pandemic,” he said.

“It’s not a delay or a go-slow on account of policy.”

The comments come after the prime minister, Anthony Albanese, said visa processing delays had been raised during his visit to Indonesia this week.

“This is an issue that, upon coming to government without going into other issues, we have found it isn’t just in this area, we have a problem processing visas,” Albanese said in Jakarta on Monday.

“There is just an extraordinary backlog.”

Engineers Australia said that migration was only one component in addressing the acute workforce shortages in the sector, an issue it said was a “complex and long-term endeavour”.

Jane MacMaster, chief engineer of Engineers Australia, said skilled migration was crucial to fill the gap between what universities and the local market can supply, but once in Australia, only about 40% of higher overseas engineers end up working in an engineering role.

“Continuing large-scale intakes of qualified engineers will not significantly develop Australia’s engineering capability alone,” she said. “Better support and utilisation of the skills currently in Australia (both through migrants and those looking to re-enter the engineering workforce) must also be a priority.”

Engineers Australia is also concerned that falling rates of secondary students taking up Stem subjects is “setting the nation up to fail” and has called on the education sector and governments to do more to encourage students into Stem.

“If we don’t do something to address this significant skills challenge, the impacts could be catastrophic for many sectors,” she said. “We will see delays to infrastructure projects and implications for Australia’s strategic priorities, such as a lack of talent to help grow sovereign supply chain capabilities.”

On 476 visas specifically, the industry body says it is working to speed up its migration skills assessments process for migrant engineers.

“For two decades Engineers Australia has performed migration skills assessments to ensure we bring the best talent and migrating workforce to Australia and is continually working to plug the engineering skills gap with policy makers, educators and industry,” MacMaster said. “Right now, we are working with government to accelerate the assessment process for migrant engineers already here.”

“We also recommend making visas and their requirements more easily understood by engineers and prospective employers.”

The home affairs department said engineering graduates were also often eligible for a range of other visas. A spokesperson said since November it had granted more than one million student, visitor, working holiday maker, temporary skilled and other temporary work visas, and that there were currently 1.61m people who held those visa types who remained offshore, despite being able to travel to Australia if fully vaccinated.

The department said it had also extended 3,000 476 visas in April for another two years.

The spokesperson said Covid had delayed the processing of many applications. Other applications had been affected by the “quality and completeness of those applications, applicants’ responsiveness to requests for information, and the complexity involved in assessing genuineness, character, health and security requirements”.