The CSIRO's senior principal scientist for strategy and foresight, Stefan Hajkowicz, told Thursday's National Medicines Symposium in Canberra healthcare had accounted for less than seven per cent of gross domestic product in the 1980s and early 1990s.

It is now running at more than nine per cent of GDP and rising every year.

"We spend 25 per cent of all government taxes on healthcare," he said. "By 2040 it will be 43 per cent [at the current rate of increase]. Nothing else in the economy grows like this. This is unsustainable."

Dr Hajkowicz the author of "Global Megatrends", said many of the challenges of the next two to three decades, such as defeating antibiotic-resistant bacteria, producing more food and incorporating evolving technologies into the economy were achievable but action needed to be taken now.

He warned of massive changes in workplaces across the country thanks to the rise of the thinking machines.

"We are seeing big leaps and bounds in artificial intelligence and its reach into what human beings do," he said.

"Anywhere between 44 to 55 per cent of all jobs people do today will be done by a robot or a computer in a 10 to 15 year period. What happened in factories with robotics is about to find its way into the banking and finance sector with a whole lot of transactional work at risk of computerisation."

The relentless increase in demand for money to spend on health remained one of the biggest elephants in the room however.

"The obesity rate continues to increase, not at the same rate – it is starting to slow – but it is still increasing," he said.

"This [ageing population and chronic illnesses] is a huge challenge. They are associated with a continued rise in healthcare expenditure. You can draw straight-line projections through state healthcare budgets in Australia and pretty much consume the whole budget within a 20 to 40-year time period if we were to continue at current rates of expenditure growth."

The good news is despite the world's increasing population future generations need not go hungry.

"The United Nations Food and Agriculture organisation forecasts we need to make 70 per cent more food in terms of calorie intake by the year 2050 in order to feed the growing population which also has increasing per capita calories consumption," he said.

"At the same time the world loses around 12 million hectares of agricultural land a year due to desertification and urbanisation. This would have made 20 million tonnes of grain if it had stayed in production."

Dr Hajkowicz said the decrease in food production capability coupled with the increase in demand was already pushing prices up.

"When the food price graph reaches a certain point we end up with violent armed conflict. There are consequences around this more from less dilemma."

Despite this the world could easily feed itself. "Thirty-five per cent of the food that is made is wasted and never eaten," he said. "Even with modest improvements in technology we can continue to meet the increased food output requirements. There is more than enough as long as we are smart. The trouble is we aren't always smart."

The future world will likely be a "realer" place than some advocates of virtual reality and its complementary technologies expect.

"There is an argument the value of the real world [will] get more important," he said. "The real experience, involving social interaction, is the one that we crave to a greater extent as we are digitally overwhelmed as well as digitally immersed."