The heads of 14 voluntary sector bodies have urged the government to do more to encourage commissioners to consider charities when commissioning public services.
The letter, signed by voluntary sector leaders including Sir Stuart Etherington, chief exeuctive of the NCVO, Sir Stephen Bubb, chief executive of Acevo, and Joe Irvin, chief executive of Navca, has been sent to Sajid Javid, economic secretary to the treasury.
The move came before today's meeting at the Treasury between Javid and representatives from sector bodies including the NCVO, the Institute of Fundraising and the Scottish Council for Voluntary Organisations.
The letter says: "Too often, decisions taken early on by commissioners effectively preclude our sector from bidding for contracts."
It says ministers must build upon improvements such as a planned new commissioning academy the Public Services (Social Value) Act, which says commissioners must consider the social value of bids for contracts; the act is expected to enhance the voluntary sector's prospects of winning.
"National and local commissioners need more encouragement and support to engage with the sector," the letter says. "This engagement with the sector is best done at the earliest stages of the commissioning process: to share information about needs and gaps in current provision and explore potential service design and delivery options before these are specified during procurement.
"Not only do we know that many larger voluntary organisations can deliver at the necessary scale but, increasingly, we know that smaller and medium-sized organisations are looking to come together as consortia in order to bid for public service contracts. If engaged appropriately in the commissioning process, we would anticipate more organisations mobilising in this way."
The letter calls for more government support for giving initiatives such as the Legacy10 campaign and for easier access for sector organisations to loan finance.
It also asks for "new measures to alleviate regulatory and tax burdens on social enterprises, in order to facilitate their growth".