The Network of Regional Youth Work Units has called on the Department for Digital, Culture, Media and Sport (DCMS) to use its promised three-year strategy for young people to significantly cut the NCS budget and instead use the money to fund youth worker training and voluntary youth services.
In a statement, the network said while it supported the government's drive to develop social action opportunities for young people, cuts in local authority budgets and grant aid for youth organisations since 2010 had seen resources for work with young people being "greatly diminished".
It said: "The government currently makes a very substantial contribution to one flagship project, National Citizen Service, and we question whether this is the right approach in a time when the youth sector and services to young people in general are under enormous pressure."
The network also said the strategy should also contain policies that ensure youth workers have access to more training and qualifications.
"Young people and communities benefit from a skilled and confident workforce and it is essential that some resources are found to make training and qualifications available, particularly to those working in voluntary sector organisations," it said.
"The sector has maintained a coherent framework for training and qualifications, including apprenticeships, and this should be extended and made more widely available."
The commitment to developing a new youth policy was made at the start of the year by former minister for civil society Rob Wilson, who lost his Reading East seat at June's general election.
Shortly after the election, the National Youth Agency said it had received assurances that the new youth strategy would go ahead, despite the civil society brief being handed to sports minister Tracey Crouch.
The Institute for Youth Work (IYW) backed the network's call for the strategy to reassess levels of support for youth services beyond NCS.
Adam Muirhead, chair of IYW, said: "The institute would welcome consideration being given to the range of cross-sector work with young people that happens outside of what has become quite a narrow field of funding support to the NCS."
In addition, the organisation wants the strategy to include ringfenced funding for youth work distributed via local authorities, votes at 16, and "investment in sector infrastructure to include the promotion of training and development pathways and the potential youth worker register/license to practice".