Around 150,000 people would have to live in Jersey by 2040 just to keep living standards the same as they are today.
That's according to a new report released by the Council of Ministers looking at government population policy.
The 2021 Census recorded a population of 103,267.
Assistant Chief Minister Deputy Lucy Stephenson says the 150,000 figure is unacceptable.
"For a population of 107,000 people, we would need 4,000 new homes and we're not there yet.
Quite clearly we just couldn't cope with it."
Ministers say they will work to reduce reliance on inward migration and to grow a sustainable economy.
That will include keeping people working longer, upskilling and embracing new technologies, automation and artificial intelligence.
The '2040 scenario' takes into account a number of factors, including Jersey's ageing population.
There are more people aged 50-90 than there were in 2011, many of those are due to retire in the next decade or so.
To reduce the reliance on inward migration, Deputy Stephenson says that the government need to maximise the potential of the local workforce.
"We already have a rise in the pension age coming into effect in the next few years.
The report eludes to some work that is going on that helps people work well, and on their terms, in their older age as we go forward."
Fewer people are also starting families in the island, also contributing to a reduction in the working-age population.
Jersey has a lower fertility rate than England and Wales at 1.32.
To keep a steady population, the fertility rate would need to be at least 2.1.
Deputy Stephenson says there is work going on to support new parents back to work.
"There are trends in Jersey that make it challenging to have children - the cost of living - and we have one of the highest rates of working women anywhere in the world, so those things do play into that."
The government is also looking at introducing automation for some jobs.
It says this would help to significantly reduce the need for inward migration and would encourage younger people to stay in Jersey or for those living elsewhere to return.
Economic Development Minister Deputy Kirsten Morel will be leading the 'Future Economy Programme', supported by the island's economic adviser Tom Holvey.