Among work handled by Vinspired, which closed its doors last November, is youth engagement for Our Bright Future - a £33m partnership led by the Wildlife Trusts to involve young people in environmental projects.
An alternative provider is now being sought by Our Bright Future to handle this work, which involves running the partnership's youth forum and supporting young members of its steering group and evaluation panel.
The role also involves supporting young people involved in the partnership in campaigning work, including organising travel to events such as parliamentary receptions.
Vinspired also ran one of the projects for Our Bright Future, called Eco Talent. This offers full-time environmental volunteer opportunities to young people in London.
Our Bright Future programme manager Cath Hare confirmed that the partnership will be looking for a new provider to handle the project.
"We are just in the process of gathering all the information we need to be able to put out a proper contract and will go out for someone else to deal with," she said.
"The youth function work is all about young people taking the lead and we have representatives from each project. They (Vinspired) dealt with a lot of that kind of arranging events with young people."
NYA chief executive Leigh Middleton said this work is "totally unaffected" by the charity's demise as it is carried out through a separate company, called Vinspired Education, which has ringfenced funding.
Documents filed with Companies House in December reveal that Vinspired owes £564,474 to creditors, including £238,000 to employees.