More than 13,000 people aged over 20 in St Helens are struggling to afford rent or a mortgage and they still live with their parents.
A report by housing charity Shelter shows 34 per cent of young adults aged 20 to 34 are still dependant on their mums and dads.
The overall total is 13,367, with 7,724 of those working.
This makes the borough the 37th highest for dependants living at home out of 324 local authorities measured.
St Helens North MP Dave Watts said: “Our problems are similar to other councils, as Britain is failing to build sufficient homes to sell and rent and we need to do something about and to reduce inflation in house prices.
“This inflation – which is about eight per cent – is making it impossible for young people to rent or buy.
“Sometimes house builders are sitting on land waiting for an increase in value. We are proposing to be able to say to developers if they don’t do the work, they will lose the land so we can increase the number of houses that are built.”
The survey commissioned by the charity also found that nearly half of young adults who live with their parents said they did so because they could not afford to rent or buy their own home.
Campbell Robb, chief executive of Shelter, said: “The ‘clipped wing generation’ are finding themselves with no choice but to remain living with mum and dad well into adulthood, as they struggle to find a home of their own.
“Rather than pumping more money into schemes like Help to Buy, we need bolder action that will meet the demand for affordable homes and not inflate prices further.
“From helping small local builders find the finance they need, to investing in a new generation of part rent, part buy homes, the solutions to our housing shortage are there for the taking.
“Politicians of all parties must now put stable homes for the next generation at the top of the agenda.”
Housing Minister Brandon Lewis said the government’s Help to Buy scheme assisted more than 35,000 people to get on the property ladder with just a fraction of the deposit they would normally need.
Mr Lewis said: “We’re determined to ensure anyone who works hard and wants to get on the property ladder has the help they need.”