While those most likely to be wearing many hats are young workers, according to data from the Australian Bureau of Statistics, more Australians overall are working multiple jobs at once.

The ABS's Jobs in Australia report was compiled from an analysis of more than 100 million tax records over six consecutive years between 2011-12 and 2016-17.

It found 15.6 per cent of employed people - about 2.1 million - were multiple job holders in 2016-17, an increase from about 1.8 million in 2011-12.

Of all the multiple job holders in 2016-17, 72.6 per cent held two jobs, 19.4 per cent held three jobs, and the remainder held four or more jobs. About 54 per cent of multiple job holders were female and 46 per cent male.

Mark Bray, a Professor of Employment Studies at the University of Newcastle, said the increase in multiple job holders was "another indicator of the way the Australian labor market is changing".

"It's the big shift over the last couple of decades in employment towards the service industries," he said.

"Away from government employment, manufacturing - all of which provided more full-time jobs. What you find in the services industry, the jobs are much more likely to be part-time and casual.

"That sector shift is a key explanation ... and absolutely what it's showing is more and more people have got part-time work and are therefore looking at a second or third job in order to get enough income to survive."

Mr Bray thought the region was likely to be on par with national statistics given a "huge decline in manufacturing", and the ABS report indicates so.

Of the 88,392 employed persons in the Newcastle local government area in 2016-17, 17 per cent (15,167) were multiple job holders. That figure had increased by 8 per cent from 2011-12.

In Lake Macquarie, 15 per cent (16,038) of the 105,926 employed persons in 2016-17 were multiple job holders, a 9 per cent increase over the six years.

Of all the multiple job holders in Australia in 2016-17, 11.9 per cent were aged under 21; 15 per cent were between 21-24; and 16 per cent were between 25-29.

Mr Bray said this was partly because organisations used casual or part-time employment as a "testing ground", but also because of a lack of of full-time jobs.

East Maitland's Michael Fisher works two jobs to achieve a full-time equivalent workload. The 27-year-old works at a Caltex service station in Heatherbrae and Reading Cinemas Maitland. He works the two jobs mainly for "financial reasons" but also to "keep active".

"When you're a casual, not all jobs are guaranteed for work," he said. "When you're working one job, if you're only getting so many shifts, you're going to want to get a second job to try and cover the extra shifts you need.

"When you bounce between the two jobs you can work out to get nearly full-time hours."

Mr Fisher had full-time work in the past, but he said it had proven hard to come by. He desires working one permanent role in the future.

"I had full-time work for a while and it was the best thing I ever hard, but then it disappeared," he said.

"Full-time work means that you have the ability for sick leave, holiday leave and you just have that job security. That is quite hard [to find], and also depends on the industry."

Adamstown's Chelsea Willis, 24, works four jobs in her chosen field of performing arts. She has a main position at Young People's Theatre in Hamilton, a second job with the Startlight Foundation, a third administration role and tutors a few hours each week. She has worked in multiple roles for about three years and is presently working about 55 to 60 hours per week.

"The original reason I started working multiple jobs was out of necessity," she said. "When I finished my training in the performing arts, I started teaching at a lot of different places. There was a period in my life when I was teaching at 10 different organisations."

Ms Willis said her early roles in the industry were only a few hours each, but she "was lucky enough" to progress through Young People's Theatre to a manager's role, which was initially about 15 hours per week.

"I keep them because it makes work interesting and I feel I get a lot of experiences from [multiple jobs]. I like keeping doors open in a few different places," she said.

Ms Willis said her life was "super busy" and she would be "lying if I said it was an easy lifestyle to have".

"I'm really lucky that I enjoy the content of the work I do," she said. "That really helps keep me going and engaged and interested.

"But there's days that I work at three different places in the same day. It's working at one and having half an hour to drive to the next, so that can be difficult. But sometimes I find it breaks up the work day because you've moved to different places and are using different parts of your brain, talking to different people."