The voluntary sector could increase its income from providing public services by up to £2bn in six key areas by 2015 if the government lives up to the rhetoric of the recent spending review, according to Acevo.
Research by the chief executives body indicates that, despite cuts in public funding, the sector's share of grants and contracts with local and central government could grow well beyond its current level.
The latest figures from the National Council for Voluntary Organisations show the sector received about £12.8bn a year in public grants and contracts in 2007/08.
In the spending review, published last month, the government said it would increase the role of the voluntary sector in service delivery areas including offender management, youth services, adult social care, early years services and public and community healthcare.
The document adds: "The government will look at setting proportions of appropriate services across the public sector that should be delivered by independent providers, such as the voluntary and community sectors and social and private enterprises."
The Acevo research, to be released in full at the organisation's annual conference on Thursday, gives estimates of the proportions by which the sector's share of public service delivery in the six areas could grow by 2015, using figures on how much it has grown in the past and the sector's capacity to deliver services.
In offender management, it says, the voluntary sector could be responsible for 12.5 per cent of services by 2015, compared with 5 per cent at present. Its proportion of community health service provision could rise from 7 per cent to 12.5 per cent.
Ralph Michell, head of policy at Acevo, said the figures were a challenge to the government to set high aspirations when deciding how big a role the voluntary sector should play in the delivery of services.
"The sector is very concerned about cuts at the moment, and obviously these will have devastating effects on some charities and some parts of the sector," he said. "But we shouldn't miss the bigger picture or lose sight of the fact that there are also big opportunities. The government is talking about opening up public service markets worth billions of pounds."