​Deaths are outnumbering births in some of Sydney's wealthiest North Shore neighbourhoods, while poorer parts of the city have experienced a baby boom.

Turramurra, Gordon, Killara, Hunters Hill and Woolwich all had a natural decrease in population between 2006 and 2014, new regional population estimates by the Bureau of Statistics reveal. The Cherrybrook area had the biggest natural population decline in the Sydney basin with 1016 more deaths than births in the nine-year period analysed.

However, this negative population trend in parts of Sydney's north was offset by internal migration – when people move into the area from other parts of the city or nation – meaning suburbs in the region with natural population declines registered a modest increase in the overall population.

The natural population declines on the North Shore contrast with parts of west and south-western Sydney, which registered strong rates of natural population growth between 2006 and 2014.

The city's biggest natural population increase was in Auburn, where births outnumbered deaths by 5100. Many households in Auburn have modest incomes compared with the rest of Sydney – Fairfax Media analysis of Tax Office data showed Auburn had Sydney's lowest average individual taxable income in 2012-13, at $36,186.

In the nearby neighbourhood of Lakemba-Wiley Park, births outpaced deaths by 4800 between 2006 and 2014, and in Bankstown, the balance in favour of births was 4600. Overall population growth in those three districts was also boosted by high rates of net overseas migration.

Bureau of Statistics demographer Andrew Howe said the settlement patterns of overseas migrants could be a factor in contrasting rates of natural population increase across the city.

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"Those areas have had a big flow of people from overseas, and if those source countries have high fertility rates it has an influence on population growth within particular regions of the city," he said.

The detailed analysis of population trends within Sydney's suburbs and districts has been made possible by new regional internal migration estimates developed by the Bureau of Statistics. These estimates draw on Medicare data as well as the Census.

Deaths outnumbered births in 17 of the 279 statistical areas tracked by the Bureau of Statistics across Greater Sydney between 2006 and 2014.

Almost all of them were located on the North Shore and the Central Coast, which has a high proportion of elderly residents. In the Erina-Green Point area, near Gosford, there were 1072 more deaths than births between 2006 and 2014. Kincumber, Picketts Valley, Toukley and Nora Head also had relatively big natural population decreases.

Mr Howe said many of the neighbourhoods with natural population decreases were popular with retirees.

"These are places that don't have a sufficient population of young females – those who have babies – to offset the death rate."

– with Conrad Walters