However, some of the Illawarra areas with the highest growth don't have a lot of vacant land.

Read more: Who is that rummaging through your bins at night?

A comparison of Australian Bureau of Statistics population data of the 10 years from 2006 and 2016 show the real story.

The 2500 postcode with its lack of empty land was the second-fastest growing in the Illawarra over that time - the population climbing by 20 per cent up to 40,150 people.

Only the 2529 area that includes the Shell Cove development saw a larger rise - 31 per cent.

The Dapto and Calderwood areas weren't even in the top five; the former's 2530 postcode came in sixth with 10 per cent growth while the latter's 2527 code was 10^th with 7 per cent.

University of Wollongong economic geographer Andrew Warren wasn't surprised that an already built-out area like the 2500 code was still growing.

Dr Warren said it was driven by the higher-density apartment buildings, which can fit many more people in the same land lot that previously held just one house.

"You'll find that consolidation around the city in terms of medium-density development has been a strategic focus for council, so that's going to increase population growth and population density in the city area," Dr Warren said.

"In many ways that's a good thing in terms of planning and infrastructure development because it tends to alleviate car dependency, which we've seen in places like Albion Park and Dapto can become a really significant issue."

Dr Warren said local councils would use population growth to target which areas were in the most need of new infrastructure.

It wasn't enough to focus on the raw statistics; there was a need to break it down in terms of categories like age, gender or ethnicity.

"The provision of services will need to have some kind of nuance to it," he said.

"For example, we know that Kiama has quite an ageing population, whereas in parts of growing areas around Dapto and Albion Park you've got a much younger population, so there's a need for investment in things like new schools in these suburbs.

"As well, if you've got a high proportion of new migrants in a suburb, what contribution is that making to population growth and the sorts of services that those groups would need?"

Between 2006 and 2016 there was just one postcode with a population decline.

The 2526 postcode including suburbs like Unanderra and Cordeaux Heights saw a 0.5 per cent decline, from 15,721 to 15,630.

The Illawarra's population growth by postcode from 2006 to 2016 - lowest to highest.

Note: not every suburb in each postcode is listed

2526 (including Unanderra, Cordeaux Heights, Farmborough Heights): minus 0.5%

2506 (Berkeley): 2%

2516 (Bulli, Bulli Tops): 2%

2528 (Warilla, Barrack Heights, Warilla, Lake Illawarra): 3%

2519 (Balgownie, Fairy Meadow, Mt Ousley, Mt Pleasant): 4%

2502 (Cringila, Lake Heights, Primbee, Warrawong): 5%

2518 (Corrimal, Bellambi): 7%

2527 (Albion Park, Albion Park Rail, Calderwood, Tullimbar): 7%

2525 (Figtree): 9%

2533 (Kiama, Minnamurra, Jamberoo): 9%

2508 (Helensburgh):10%

2530 (Dapto, Kanahooka, West Dapto): 10%

2515 (Thirroul, Austinmer, Wombarra): 12%

2505 (Kemblawarra, Port Kembla): 14%

2517 (Woonona, Russell Vale): 17%

2500 (Wollongong, Keiraville, Gwynneville): 20%

2529 (Shellharbour Shell Cove, Flinders): 31%

We depend on subscription revenue to support our journalism. If you are able, please subscribe here. If you are already a subscriber, thank you for your support.

Subscribe to our newsletters