The research consultancy surveyed a sample of 1,000 over-16s. It found that 62 per cent rated larger charities such as Oxfam and Cancer Research UK as more professional and able to deliver public services - but 51 per cent also believed they were more wasteful.
Kinross + Render CEO Sara Render suggested that larger charities should combat this perception by better explaining the benefits of seemingly wasteful behaviour.
'In some cases, although I have yet to come across one, it might be that the best course of action is better management and related communication about related impacts on the cost base. In others, it will be a case of explaining the long-term benefits and importance of work that is necessary but could be misconstrued as "wasteful",' said Render.
She pointed to lobbying and long-term research programmes as harder to justify.
The research found that while there is little overt enthusiasm for donating to large organisations, there is a significant 'loyal hardcore' who prefer the small or local option. Small charities are deemed to be more volunteer-led, more regionally focused, more friendly, more understanding of the needs of those they help and more trustworthy, but are also perceived as being more 'amateurish'.
Forty per cent of the public claimed to prefer to donate to a charity manned by volunteers; 18 per cent to a charity with an annual income below £10,000; and 23 per cent to a charity working in their nearest town.
Separately, the Royal British Legion has been ranked as the most effective charity at campaigning in a survey of MPs, by nfpSynergy, for the second consecutive quarter.