A report by London Youth says a growing population, a huge reduction in funding for youth services and pressures on housing and communities have left young Londoners fearing they will miss out on opportunities to enjoy living in the capital.
In addition to calling for clear local authority plans, they also want young people to have more of a say in policy decisions, particularly around regeneration.
Private, voluntary and public sector funders also need to work better together to prioritise services that can be accessed by all young people, not just the most vulnerable.
A shift in youth services strategy in recent years to focus dwindling resources on targeted, rather than universal, youth provision was a key concern raised in the report, called Young People's Capital of the World?
The high cost of living in the capital was another problem, which is leaving many young people feeling excluded from their communities and fearful about how they will make the move into independent living, says the report, which involved interviews with young people across five London boroughs as well as the views of youth professionals.
The effect of a lack of access to outside space and clean air on mental health and obesity rates are other problems raised by the young people interviewed.
London Youth chief executive Rosemary Watt-Wyness said: "Young people do face a huge amount of pressure as London changes. And cuts to services mean that many simply can't access support outside of school.
"Everyone acknowledges that local authority funding is tight, but that does not negate the need for clear local strategies that respond to need.
"We want this report to set a clear direction for young people's policy in London, and to help those who make decisions about investment and development to make better choices to support our future generations of Londoners."
In January it emerged that youth services in London have had their budgets cut by £22m and lost more than a third of their staff over the last five years.
Among councils planning cuts this year is the London Borough of Hounslow, which in January launched a consultation over a proposal to slash its youth services budget by 75 per cent. A decision is expected next month.
The London Mayor's Office has been contacted for comment.