Jersey is at 'saturation point' says environmental campaigner
A Jersey environmental campaigner said the island had reached saturation point in population growth.
A new population model published by the States of Jersey shows that there could be 120,000 people living in Jersey by 2035.
Dr Mark Forskitt said he was shocked by the figures and concerned at the strain it would put on island services.
The States used the 2011 census to draw up predictions of population size to assess future housing and health needs.
Dr Forskitt said: "That is a lot of people. It is more than we've got now and the problem with having more people is that you have more demand, not just jobs but also schools, transport, food, water.
"It is part of the ever growing cyclic system of more and more and more and at some point it has to stop."
The island has a surface area of 46.13 sq miles and as of June 2012 a population of 98,000.
There are currently 2,121 people per square mile in Jersey, compared with 661.9 per square mile in the UK. Hong Kong has 16,576 people per square mile.
Chief Minister Senator Ian Gorst said if the population grew too much public services would struggle to cope.
"If we don't allow people to come who are going to bring jobs, who are going to bring inward investment then the dependency ratio, the number of people working to the number of people retired, if that becomes to small then we have a problem providing services to those people who are retired," he said.
About 700 people move to Jersey each year and about 300 people leave.