Children's charity SOS Children UK wants every British NGO to pledge not to use any money donated to support victims of the Haiti earthquake to pay for central functions.
The charity has set up a website that asks other charities to sign up, promising they will not use funds raised for Haiti to pay for advertising, fundraising or administration.
Andrew Cates, chief executive of SOS Children, said there was no reason to take money out of Haiti donations to support central functions because charities should already have budgeted for those costs.
"The situation in Haiti is so dire and unexpected, we think we should do something a bit special for them," he said. "No charities should be making any deductions from donations because charities had already fixed their 2010 budgets when the tragedy in Haiti happened, so 100 per cent of donations should go to Haiti."
Louise Richards, director of policy and campaigns at the Institute of Fundraising, said investments such as advertising in the UK created huge returns for charities.
"We realise money was designated before Haiti, but we've heard from our associated charities that in these kinds of appeals every £1 spend on things like advertising generates hundreds, if not thousands of pounds return in donations," she said. "People generally realise that investing in additional appeals is rightly funded by donations."