The lottery distributors' current levels of third sector funding should be set as a minimum benchmark for the future, according to Stephen Bubb, head of chief executives' body Acevo.
In a letter to the new culture secretary Jeremy Hunt, Bubb calls on the government to establish the proportion of expenditure each distributor spends on the third sector and make a commitment that future spending will not drop below that level.
Bubb says this should be "irrespective of changes to the division of funds between different areas of activity or different lottery distributors".
The proposal has come in response to a pledge in the coalition government's programme for government to ensure more lottery money goes into "sport, the arts and heritage".
"I would be concerned if your plan to direct more National Lottery funding to these fields had the unintended consequence of less National Lottery money going to civil society and more going to the public sector," he writes.
In a speech last Wednesday, Hunt said he would place an order before parliament giving arts, sports and heritage good causes 20 per cent each of lottery funding, with the remaining 40 per cent going to the Big Lottery Fund. At the moment the BLF gets 50 per cent.
The Acevo chief also wants the Department for Culture, Media and Sport to ensure that its plan to limit the lottery distributors' administration costs to 5 per cent of income does not result in the funding of "fewer, larger organisations".