The population of NSW is now expected to grow to almost 10 million in the next two decades, outpacing previous forecasts.

Updated population projection data released by Planning Minister Rob Stokes on Monday show the number of people living in the state is expected to grow from 7,218,528 in 2011 to 9,925,550 by 2036.

The bump represents 225,000 more people than forecast in 2014 projections.

A net total of 1.74 million people are expected to arrive from overseas to make their home in NSW between 2011 and 2036, while a net 370,000 people from New South Wales are expected to move interstate over the same period.

Metropolitan Sydney alone is now expected to grow from 4,286,217 in 2011 to 6,421,850 in 2036 - another 2,135,633 residents.

Premier Mike Baird acknowledged the higher headcount would put more pressure on a city already grappling with traffic jams and low housing affordability.

'We want not just to deal with the current congestion we have but to deal with growth,' Mr Baird told reporters in Sydney on Monday morning.

'That's why the lease (of the state's electricity networks) was so important, that's why the $20 billion we're investing in metro rail, in improving our roads, in schools, in hospitals, is critically required. And the good news is that we are delivering.'

Under previous forecasts, it was thought that 664,000 additional homes would be needed in Sydney between 2011 and 2031, according to the government.

The revised population data suggest 726,000 homes will be required between now and 2036.

Wonder what's causing that? 

No .... that's for sure.

But it doesn't take much to figure the demographics going by the topics of certain threads here.